diff --git a/libraries/biomes/README.md b/libraries/biomes/README.md
new file mode 100644
index 00000000..8fa49f5f
--- /dev/null
+++ b/libraries/biomes/README.md
@@ -0,0 +1,41 @@
+# Biomes API
+
+The Biomes API provides events and utilities for registering and working with biomes.
+
+## Registering Custom Biomes
+
+Biome registration should be done in a listener to the `REGISTER_BIOMES` event. The `BiomeRegistry` class provides utility methods for registering biomes.
+
+An example is shown below.
+
+```java
+package com.example;
+
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.entrypoints.api.ModInitializer;
+
+public class ExampleInitializer implements ModInitializer {
+
+	@Override
+	public void init() {
+		BiomeEvents.REGISTER_BIOMES.register(ExampleBiomes::init);
+	}
+}
+```
+
+```java
+package com.example;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.BiomeRegistry;
+import net.ornithemc.osl.core.util.NamespacedIdentifiers;
+
+public final class ExampleBiomes {
+
+	public static final CookieBiome COOKIE = BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome(new Biome.Settings().setName("Cookie")));
+
+	public static void init() {
+	}
+}
+```
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/build.gradle b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/gradle.properties b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/gradle.properties
new file mode 100644
index 00000000..03ed48f0
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/gradle.properties
@@ -0,0 +1,4 @@
+min_mc_version = 1.8.2-pre5
+max_mc_version = 15w51b
+
+minecraft_version = 1.8.9
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..86e85031
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,106 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param id    the numerical ID of the biome.
+	 * @param key   the namespaced ID of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 * 
+	 * @deprecated use {@linkplain #register(NamespacedIdentifier, Biome)}
+	 *             or {@linkplain #register(ResourceKey, Biome)} instead.
+	 */
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		return BiomeRegistryImpl.register(id, key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..06d6a59b
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,13 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.Registry;
+
+public interface BiomeExtension {
+
+	Registry<Biome> REGISTRY = BiomeRegistryImpl.REGISTRY;
+	int AUTO_ASSIGN_ID = -172;
+
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..46583dba
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,111 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.biomes.impl.biome.BiomeIdFixer;
+import net.ornithemc.osl.registries.api.registry.Registries;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.RegistriesImpl;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = Registries.registerSimple(RegistryKeys.BIOME, () -> Biome.BY_ID.getClass());
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, identifier, biome);
+		}
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, key, biome);
+		}
+	}
+
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.id != id) {
+				throw new IllegalArgumentException("ID " + id + " does not match biome ID " + biome.id + " for " + key);
+			}
+
+			return Registry.register(REGISTRY, id, key, biome);
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+		SyncedRegistries.registerFixer(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/id"), new BiomeIdFixer());
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		VanillaBiomes.init();
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+
+	public static void registerUnknownBiomes() {
+		for (Biome biome : Biome.BY_ID) {
+			if (biome != null && REGISTRY.getIdentifier(biome) == null) {
+				NamespacedIdentifier identifier = NamespacedIdentifiers.from("osl", "biome_" + biome.id);
+
+				RegistriesImpl.LOGGER.warn("Biome {}/{}", biome.id, biome.getClass().getSimpleName() + " was not registered to OSL's Biome registry! Adding it as '" + identifier + "'...");
+				BiomeRegistryImpl.register(identifier, biome);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
new file mode 100644
index 00000000..e52a2ca8
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
@@ -0,0 +1,45 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.List;
+import java.util.Set;
+
+import org.objectweb.asm.tree.ClassNode;
+
+import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
+import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
+
+public class BiomesMixinPlugin implements IMixinConfigPlugin {
+
+	public static final boolean BIOME_IDS_BEYOND_255_SUPPORTED = false;
+
+	@Override
+	public void onLoad(String mixinPackage) {
+	}
+
+	@Override
+	public String getRefMapperConfig() {
+		return null;
+	}
+
+	@Override
+	public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
+		return true;
+	}
+
+	@Override
+	public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {
+	}
+
+	@Override
+	public List<String> getMixins() {
+		return null;
+	}
+
+	@Override
+	public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+
+	@Override
+	public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
new file mode 100644
index 00000000..a17199dd
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
@@ -0,0 +1,146 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+
+public final class VanillaBiomes {
+
+	/**
+	 * Namespaced IDs were introduced in 1.9. Before then, the numerical IDs
+	 * were the only unique identifiers for biomes. Here we assign namespaced
+	 * IDs to pre-1.9 biomes, matching the 1.9 IDs  where possible.
+	 */
+	private static final String[] IDENTIFIERS = {
+		// grouped per 10 for easier lookup
+
+		"ocean",
+		"plains",
+		"desert",
+		"extreme_hills",
+		"forest",
+		"taiga",
+		"swampland",
+		"river",
+		"hell",
+		"sky",
+
+		"frozen_ocean",
+		"frozen_river",
+		"ice_flats",
+		"ice_mountains",
+		"mushroom_island",
+		"mushroom_island_shore",
+		"beaches",
+		"desert_hills",
+		"forest_hills",
+		"taiga_hills",
+
+		"smaller_extreme_hills",
+		"jungle",
+		"jungle_hills",
+		"jungle_edge",
+		"deep_ocean",
+		"stone_beach",
+		"cold_beach",
+		"birch_forest",
+		"birch_forest_hills",
+		"roofed_forest",
+
+		"taiga_cold",
+		"taiga_cold_hills",
+		"redwood_taiga",
+		"redwood_taiga_hills",
+		"extreme_hills_with_trees",
+		"savanna",
+		"savanna_rock",
+		"mesa",
+		"mesa_rock",
+		"mesa_clear_rock"
+	};
+	private static final String[] MUTATED_IDENTIFIERS = {
+		null,
+		"mutated_plains",
+		"mutated_desert",
+		"mutated_extreme_hills",
+		"mutated_forest",
+		"mutated_taiga",
+		"mutated_swampland",
+		null,
+		null,
+		null,
+
+		null,
+		null,
+		"mutated_ice_flats",
+		null,
+		null,
+		null,
+		null,
+		null,
+		null,
+		null,
+
+		null,
+		"mutated_jungle",
+		null,
+		"mutated_jungle_edge",
+		null,
+		null,
+		null,
+		"mutated_birch_forest",
+		"mutated_birch_forest_hills",
+		"mutated_roofed_forest",
+
+		"mutated_taiga_cold",
+		null,
+		"mutated_redwood_taiga",
+		"mutated_redwood_taiga_hills",
+		"mutated_extreme_hills_with_trees",
+		"mutated_savanna",
+		"mutated_savanna_rock",
+		"mutated_mesa",
+		"mutated_mesa_rock",
+		"mutated_mesa_clear_rock"
+	};
+
+	public static final int MAX_ID = 255;
+	public static final int MUTATED_ID_OFFSET = 128;
+
+	static void init() {
+		for (Field f : Biome.class.getDeclaredFields()) {
+			if (Modifier.isStatic(f.getModifiers()) && Biome.class.isAssignableFrom(f.getType())) {
+				try {
+					Biome biome = (Biome) f.get(null);
+
+					if (biome != null) {
+						register(biome);
+					}
+				} catch (Throwable t) {
+				}
+			}
+		}
+	}
+
+	private static void register(Biome biome) {
+		if (biome.id >= 0 && biome.id < IDENTIFIERS.length) {
+			String identifier = IDENTIFIERS[biome.id];
+
+			if (identifier != null) {
+				BiomeRegistryImpl.register(NamespacedIdentifiers.from(identifier), biome);
+			}
+		}
+
+		if (biome.id >= 0 && biome.id < MUTATED_IDENTIFIERS.length) {
+			Biome mutated = Biome.BY_ID[biome.id + MUTATED_ID_OFFSET];
+			String identifier = MUTATED_IDENTIFIERS[biome.id];
+
+			if (identifier != null) {
+				BiomeRegistryImpl.register(NamespacedIdentifiers.from(identifier), mutated);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..1b77c6af
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,6 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
new file mode 100644
index 00000000..1bacf15f
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
@@ -0,0 +1,19 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.registries.api.registry.sync.IdFixer;
+
+public class BiomeIdFixer implements IdFixer {
+
+	@Override
+	public void apply() {
+		for (int id = 0; id < Biome.BY_ID.length; id++) {
+			Biome biome = Biome.BY_ID[id];
+
+			if (biome != null) {
+				biome.id = id;
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..60bbefe9
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,132 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.objectweb.asm.Opcodes;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Mutable;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.At.Shift;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.BiomesMixinPlugin;
+import net.ornithemc.osl.biomes.impl.VanillaBiomes;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.ArrayMapper;
+import net.ornithemc.osl.registries.api.registry.sync.DynamicArray;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension {
+
+	@Shadow @Final @Mutable
+	private static Biome[] BY_ID;
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			ordinal = 0
+		)
+	)
+	private static void osl$biomes$registerBiomes(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+		BiomeRegistryImpl.registerUnknownBiomes();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerArrayMappers(CallbackInfo ci) {
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/by_id"), ArrayMapper.of(() -> BY_ID, a -> BY_ID = a));
+	}
+
+	@ModifyVariable(
+		method = "<init>",
+		argsOnly = true,
+		ordinal = 0,
+		at = @At(
+			value = "INVOKE",
+			target = "Ljava/lang/Object;<init>()V",
+			shift = Shift.AFTER
+		)
+	)
+	private int osl$biomes$handleAutoAssignId(int id) {
+		if (id == AUTO_ASSIGN_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(BY_ID);
+
+			// keep 0-255 free for all Vanilla biomes
+			if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id <= VanillaBiomes.MAX_ID) {
+				id = VanillaBiomes.MAX_ID + 1;
+			}
+		}
+
+		if (!BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id > VanillaBiomes.MAX_ID) {
+			throw new IllegalStateException("Biome IDs above 255 are not supported at this time!"
+					+ " Biome IDs should be limited to the range 0-255"
+					+ " unless the save format has been modified to support IDs beyond 255.");
+		}
+
+		return id;
+	}
+
+	@Inject(
+		method = "<init>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			args = "array=set"
+		)
+	)
+	private void osl$biomes$growArrays(int id, CallbackInfo ci) {
+		int capacity = id + 1;
+
+		BY_ID = DynamicArray.grow(BY_ID, capacity);
+	}
+
+	@WrapOperation(
+		method = "mutate()Lnet/minecraft/world/biome/Biome;",
+		at = @At(
+			value = "INVOKE",
+			target = "Lnet/minecraft/world/biome/Biome;mutate(I)Lnet/minecraft/world/biome/Biome;"
+		)
+	)
+	private static Biome osl$biomes$handleAutoAssignIdForMutatedBiomes(Biome original, int id, Operation<Biome> op) {
+		if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && original.id > VanillaBiomes.MAX_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(BY_ID);
+		}
+
+		return op.call(original, id);
+	}
+}
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..9ee73d6c
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc1.8.2-pre5-mc15w51b",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.8.2-rc.5 \u003c\u003d1.9-alpha.15.51.b",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..65138a95
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,17 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(I)V
+transitive-accessible	method	net/minecraft/world/biome/Biome	setTemperatureAndDownfall	(FF)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setHeight	(Lnet/minecraft/world/biome/Biome$Height;)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	disableRain	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setSnowy	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setName	(Ljava/lang/String;)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setMutatedColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setBaseColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setColor	(IZ)Lnet/minecraft/world/biome/Biome;
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+
+accessible	field	net/minecraft/world/biome/Biome	BY_ID	[Lnet/minecraft/world/biome/Biome;
+mutable	field	net/minecraft/world/biome/Biome	id	I
diff --git a/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..a674432b
--- /dev/null
+++ b/libraries/biomes/biomes-mc1.8.2-pre5-mc15w51b/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,17 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/build.gradle b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/gradle.properties b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/gradle.properties
new file mode 100644
index 00000000..98b53053
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/gradle.properties
@@ -0,0 +1,7 @@
+min_mc_version = 13w36a
+max_mc_version = 1.8.2-pre4
+
+minecraft_version = 1.7.2
+raven_build = 1
+sparrow_build = 1
+nests_build = 3
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..86e85031
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,106 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param id    the numerical ID of the biome.
+	 * @param key   the namespaced ID of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 * 
+	 * @deprecated use {@linkplain #register(NamespacedIdentifier, Biome)}
+	 *             or {@linkplain #register(ResourceKey, Biome)} instead.
+	 */
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		return BiomeRegistryImpl.register(id, key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..06d6a59b
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,13 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.Registry;
+
+public interface BiomeExtension {
+
+	Registry<Biome> REGISTRY = BiomeRegistryImpl.REGISTRY;
+	int AUTO_ASSIGN_ID = -172;
+
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..46583dba
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,111 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.biomes.impl.biome.BiomeIdFixer;
+import net.ornithemc.osl.registries.api.registry.Registries;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.RegistriesImpl;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = Registries.registerSimple(RegistryKeys.BIOME, () -> Biome.BY_ID.getClass());
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, identifier, biome);
+		}
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, key, biome);
+		}
+	}
+
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.id != id) {
+				throw new IllegalArgumentException("ID " + id + " does not match biome ID " + biome.id + " for " + key);
+			}
+
+			return Registry.register(REGISTRY, id, key, biome);
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+		SyncedRegistries.registerFixer(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/id"), new BiomeIdFixer());
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		VanillaBiomes.init();
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+
+	public static void registerUnknownBiomes() {
+		for (Biome biome : Biome.BY_ID) {
+			if (biome != null && REGISTRY.getIdentifier(biome) == null) {
+				NamespacedIdentifier identifier = NamespacedIdentifiers.from("osl", "biome_" + biome.id);
+
+				RegistriesImpl.LOGGER.warn("Biome {}/{}", biome.id, biome.getClass().getSimpleName() + " was not registered to OSL's Biome registry! Adding it as '" + identifier + "'...");
+				BiomeRegistryImpl.register(identifier, biome);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
new file mode 100644
index 00000000..19b6a9e8
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
@@ -0,0 +1,54 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.List;
+import java.util.Set;
+
+import org.objectweb.asm.tree.ClassNode;
+
+import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
+import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
+
+import net.ornithemc.osl.core.impl.util.MinecraftVersion;
+
+public class BiomesMixinPlugin implements IMixinConfigPlugin {
+
+	public static final boolean BIOME_IDS_BEYOND_255_SUPPORTED = false;
+
+	@Override
+	public void onLoad(String mixinPackage) {
+	}
+
+	@Override
+	public String getRefMapperConfig() {
+		return null;
+	}
+
+	@Override
+	public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
+		if ("net.ornithemc.osl.biomes.impl.mixin.common.BiomeMixinNew".equals(mixinClassName)) {
+			return MinecraftVersion.resolve().compareTo("14w05a") >= 0;
+		}
+		if ("net.ornithemc.osl.biomes.impl.mixin.common.BiomeMixinOld".equals(mixinClassName)) {
+			return MinecraftVersion.resolve().compareTo("14w05a") < 0;
+		}
+
+		return true;
+	}
+
+	@Override
+	public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {
+	}
+
+	@Override
+	public List<String> getMixins() {
+		return null;
+	}
+
+	@Override
+	public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+
+	@Override
+	public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
new file mode 100644
index 00000000..a17199dd
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
@@ -0,0 +1,146 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+
+public final class VanillaBiomes {
+
+	/**
+	 * Namespaced IDs were introduced in 1.9. Before then, the numerical IDs
+	 * were the only unique identifiers for biomes. Here we assign namespaced
+	 * IDs to pre-1.9 biomes, matching the 1.9 IDs  where possible.
+	 */
+	private static final String[] IDENTIFIERS = {
+		// grouped per 10 for easier lookup
+
+		"ocean",
+		"plains",
+		"desert",
+		"extreme_hills",
+		"forest",
+		"taiga",
+		"swampland",
+		"river",
+		"hell",
+		"sky",
+
+		"frozen_ocean",
+		"frozen_river",
+		"ice_flats",
+		"ice_mountains",
+		"mushroom_island",
+		"mushroom_island_shore",
+		"beaches",
+		"desert_hills",
+		"forest_hills",
+		"taiga_hills",
+
+		"smaller_extreme_hills",
+		"jungle",
+		"jungle_hills",
+		"jungle_edge",
+		"deep_ocean",
+		"stone_beach",
+		"cold_beach",
+		"birch_forest",
+		"birch_forest_hills",
+		"roofed_forest",
+
+		"taiga_cold",
+		"taiga_cold_hills",
+		"redwood_taiga",
+		"redwood_taiga_hills",
+		"extreme_hills_with_trees",
+		"savanna",
+		"savanna_rock",
+		"mesa",
+		"mesa_rock",
+		"mesa_clear_rock"
+	};
+	private static final String[] MUTATED_IDENTIFIERS = {
+		null,
+		"mutated_plains",
+		"mutated_desert",
+		"mutated_extreme_hills",
+		"mutated_forest",
+		"mutated_taiga",
+		"mutated_swampland",
+		null,
+		null,
+		null,
+
+		null,
+		null,
+		"mutated_ice_flats",
+		null,
+		null,
+		null,
+		null,
+		null,
+		null,
+		null,
+
+		null,
+		"mutated_jungle",
+		null,
+		"mutated_jungle_edge",
+		null,
+		null,
+		null,
+		"mutated_birch_forest",
+		"mutated_birch_forest_hills",
+		"mutated_roofed_forest",
+
+		"mutated_taiga_cold",
+		null,
+		"mutated_redwood_taiga",
+		"mutated_redwood_taiga_hills",
+		"mutated_extreme_hills_with_trees",
+		"mutated_savanna",
+		"mutated_savanna_rock",
+		"mutated_mesa",
+		"mutated_mesa_rock",
+		"mutated_mesa_clear_rock"
+	};
+
+	public static final int MAX_ID = 255;
+	public static final int MUTATED_ID_OFFSET = 128;
+
+	static void init() {
+		for (Field f : Biome.class.getDeclaredFields()) {
+			if (Modifier.isStatic(f.getModifiers()) && Biome.class.isAssignableFrom(f.getType())) {
+				try {
+					Biome biome = (Biome) f.get(null);
+
+					if (biome != null) {
+						register(biome);
+					}
+				} catch (Throwable t) {
+				}
+			}
+		}
+	}
+
+	private static void register(Biome biome) {
+		if (biome.id >= 0 && biome.id < IDENTIFIERS.length) {
+			String identifier = IDENTIFIERS[biome.id];
+
+			if (identifier != null) {
+				BiomeRegistryImpl.register(NamespacedIdentifiers.from(identifier), biome);
+			}
+		}
+
+		if (biome.id >= 0 && biome.id < MUTATED_IDENTIFIERS.length) {
+			Biome mutated = Biome.BY_ID[biome.id + MUTATED_ID_OFFSET];
+			String identifier = MUTATED_IDENTIFIERS[biome.id];
+
+			if (identifier != null) {
+				BiomeRegistryImpl.register(NamespacedIdentifiers.from(identifier), mutated);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..1b77c6af
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,6 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
new file mode 100644
index 00000000..1bacf15f
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
@@ -0,0 +1,19 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.registries.api.registry.sync.IdFixer;
+
+public class BiomeIdFixer implements IdFixer {
+
+	@Override
+	public void apply() {
+		for (int id = 0; id < Biome.BY_ID.length; id++) {
+			Biome biome = Biome.BY_ID[id];
+
+			if (biome != null) {
+				biome.id = id;
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..6cdc0141
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,87 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.objectweb.asm.Opcodes;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Mutable;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.At.Shift;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomesMixinPlugin;
+import net.ornithemc.osl.biomes.impl.VanillaBiomes;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.ArrayMapper;
+import net.ornithemc.osl.registries.api.registry.sync.DynamicArray;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension {
+
+	@Shadow @Final @Mutable
+	private static Biome[] BY_ID;
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerArrayMappers(CallbackInfo ci) {
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/by_id"), ArrayMapper.of(() -> BY_ID, a -> BY_ID = a));
+	}
+
+	@ModifyVariable(
+		method = "<init>",
+		argsOnly = true,
+		ordinal = 0,
+		at = @At(
+			value = "INVOKE",
+			target = "Ljava/lang/Object;<init>()V",
+			shift = Shift.AFTER
+		)
+	)
+	private int osl$biomes$handleAutoAssignId(int id) {
+		if (id == AUTO_ASSIGN_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(BY_ID);
+
+			// keep 0-255 free for all Vanilla biomes
+			if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id <= VanillaBiomes.MAX_ID) {
+				id = VanillaBiomes.MAX_ID + 1;
+			}
+		}
+
+		if (!BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id > VanillaBiomes.MAX_ID) {
+			throw new IllegalStateException("Biome IDs above 255 are not supported at this time!"
+					+ " Biome IDs should be limited to the range 0-255"
+					+ " unless the save format has been modified to support IDs beyond 255.");
+		}
+
+		return id;
+	}
+
+	@Inject(
+		method = "<init>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			args = "array=set"
+		)
+	)
+	private void osl$biomes$growArrays(int id, CallbackInfo ci) {
+		int capacity = id + 1;
+
+		BY_ID = DynamicArray.grow(BY_ID, capacity);
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinNew.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinNew.java
new file mode 100644
index 00000000..3d1e3499
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinNew.java
@@ -0,0 +1,63 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.objectweb.asm.Opcodes;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.BiomesMixinPlugin;
+import net.ornithemc.osl.biomes.impl.VanillaBiomes;
+import net.ornithemc.osl.registries.api.registry.sync.DynamicArray;
+
+@Mixin(Biome.class)
+public class BiomeMixinNew {
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			ordinal = 0
+		)
+	)
+	private static void osl$biomes$registerBiomes(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+		BiomeRegistryImpl.registerUnknownBiomes();
+	}
+
+	@WrapOperation(
+		method = "mutate()Lnet/minecraft/world/biome/Biome;",
+		at = @At(
+			value = "INVOKE",
+			target = "Lnet/minecraft/world/biome/Biome;mutate(I)Lnet/minecraft/world/biome/Biome;"
+		)
+	)
+	private static Biome osl$biomes$handleAutoAssignIdForMutatedBiomes(Biome original, int id, Operation<Biome> op) {
+		if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && original.id > VanillaBiomes.MAX_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(Biome.BY_ID);
+		}
+
+		return op.call(original, id);
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinOld.java b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinOld.java
new file mode 100644
index 00000000..08eab329
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixinOld.java
@@ -0,0 +1,64 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.objectweb.asm.Opcodes;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+
+import net.minecraft.world.biome.Biome;
+import net.minecraft.world.biome.MutatedBiome;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.BiomesMixinPlugin;
+import net.ornithemc.osl.biomes.impl.VanillaBiomes;
+import net.ornithemc.osl.registries.api.registry.sync.DynamicArray;
+
+@Mixin(Biome.class)
+public class BiomeMixinOld {
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			ordinal = 0
+		)
+	)
+	private static void osl$biomes$registerBiomes(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+		BiomeRegistryImpl.registerUnknownBiomes();
+	}
+
+	@WrapOperation(
+		method = "mutate",
+		at = @At(
+			value = "NEW",
+			target = "net/minecraft/world/biome/MutatedBiome"
+		)
+	)
+	private static MutatedBiome osl$biomes$handleAutoAssignIdForMutatedBiomes(int id, Biome original, Operation<MutatedBiome> op) {
+		if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && original.id > VanillaBiomes.MAX_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(Biome.BY_ID);
+		}
+
+		return op.call(id, original);
+	}
+}
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..19d52978
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc13w36a-mc1.8.2-pre4",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.7-alpha.13.36.a \u003c\u003d1.8.2-rc.4",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..65138a95
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,17 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(I)V
+transitive-accessible	method	net/minecraft/world/biome/Biome	setTemperatureAndDownfall	(FF)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setHeight	(Lnet/minecraft/world/biome/Biome$Height;)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	disableRain	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setSnowy	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setName	(Ljava/lang/String;)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setMutatedColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setBaseColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setColor	(IZ)Lnet/minecraft/world/biome/Biome;
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+
+accessible	field	net/minecraft/world/biome/Biome	BY_ID	[Lnet/minecraft/world/biome/Biome;
+mutable	field	net/minecraft/world/biome/Biome	id	I
diff --git a/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..a674432b
--- /dev/null
+++ b/libraries/biomes/biomes-mc13w36a-mc1.8.2-pre4/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,17 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/build.gradle b/libraries/biomes/biomes-mc16w02a-mc18w05a/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/gradle.properties b/libraries/biomes/biomes-mc16w02a-mc18w05a/gradle.properties
new file mode 100644
index 00000000..5d40c0ac
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/gradle.properties
@@ -0,0 +1,4 @@
+min_mc_version = 16w02a
+max_mc_version = 18w05a
+
+minecraft_version = 1.12.2
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..bc8fb566
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,91 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..4e8867f6
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,14 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtension {
+
+	interface SettingsExtension {
+
+		Biome.Settings parent(NamespacedIdentifier identifier);
+
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java
new file mode 100644
index 00000000..0ca2ddfc
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java
@@ -0,0 +1,20 @@
+package net.ornithemc.osl.biomes.impl;
+
+import net.minecraft.resource.Identifier;
+import net.minecraft.util.registry.IdRegistry;
+import net.minecraft.world.biome.Biome;
+
+/**
+ * The biome registry is created and populated in Biome's class initializer.
+ * This breaks OSL's usual pattern of registering the registry in the API entrypoint but
+ * triggering registry population during bootstrapping, since OSL has to wrap the Vanilla
+ * registry which is not possible without triggering Biome class load and registry
+ * population.
+ * The solution: move the Vanilla registry to another class and replace the IdRegistry
+ * reference in Biome with this one.
+ */
+public final class BiomeIdRegistry {
+
+	public static final IdRegistry<Identifier, Biome> REGISTRY = new IdRegistry<>();
+
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..c00d2e7d
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,99 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.VanillaRegistries;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = VanillaRegistries.registerSimple(RegistryKeys.BIOME, BiomeIdRegistry.REGISTRY, () -> Biome.REGISTRY);
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(identifier, biome);
+			}
+
+			return Registry.register(REGISTRY, identifier, biome);
+		}
+	}
+
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(key.identifier(), biome);
+			}
+
+			return Registry.register(REGISTRY, key, biome);
+		}
+	}
+
+	private static void registerBiomeMutation(NamespacedIdentifier identifier, Biome biome) {
+		NamespacedIdentifier parentIdentifier = biome.osl$biomes$getParentIdentifier();
+		Biome parent = REGISTRY.get(parentIdentifier);
+
+		if (parent == null) {
+			throw new IllegalStateException("Error registering mutated biome " + identifier + ": parent " + parentIdentifier + " does not exist!");
+		} else {
+			Biome.MUTATED_BIOMES.put(biome, REGISTRY.getId(parent));
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
new file mode 100644
index 00000000..e64d1669
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
@@ -0,0 +1,10 @@
+package net.ornithemc.osl.biomes.impl.access;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeAccess {
+
+	default NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		throw new AbstractMethodError();
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..bc8a9dc4
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,17 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+
+	interface SettingsExtensionImpl extends SettingsExtension {
+
+		@Override
+		default Biome.Settings parent(NamespacedIdentifier identifier) {
+			throw new AbstractMethodError();
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..e1d87b9e
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,74 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.resource.Identifier;
+import net.minecraft.util.Id2ObjectBiMap;
+import net.minecraft.util.registry.IdRegistry;
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomeIdRegistry;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.access.BiomeAccess;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.Id2ObjectBiMapMapper;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension, BiomeAccess {
+
+	@Shadow @Final
+	public static Id2ObjectBiMap<Biome> MUTATED_BIOMES;
+
+	@Shadow @Final
+	private String parent;
+
+	@Redirect(
+		method = "<clinit>",
+		at = @At(
+			value = "NEW",
+			target = "net/minecraft/util/registry/IdRegistry"
+		)
+	)
+	private static IdRegistry<Identifier, Biome> osl$biomes$replaceIdRegistry() {
+		// this allows us to register the biome registry in
+		// the API entrypoint without triggering a Biome class load
+		return BiomeIdRegistry.REGISTRY;
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerBiomesAndMappers(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("mutated_biome"), Id2ObjectBiMapMapper.of(MUTATED_BIOMES));
+	}
+
+	@Override
+	public NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		return this.parent == null ? null : NamespacedIdentifiers.parse(this.parent);
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeSettingsMixin.java b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeSettingsMixin.java
new file mode 100644
index 00000000..f906a416
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeSettingsMixin.java
@@ -0,0 +1,22 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+@Mixin(Biome.Settings.class)
+public class BiomeSettingsMixin implements BiomeExtension.SettingsExtension {
+
+	@Shadow
+	public String parent;
+
+	@Override
+	public Biome.Settings parent(NamespacedIdentifier identifier) {
+		this.parent = identifier.toString();
+		return (Biome.Settings) (Object) this;
+	}
+}
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..98f2768e
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc16w02a-mc18w05a",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.9-alpha.16.2.a \u003c\u003d1.13-alpha.18.5.a",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..bf7db77f
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,16 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(Lnet/minecraft/world/biome/Biome$Settings;)V
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	temperature	(F)Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	downfall	(F)Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	depth	(F)Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	scale	(F)Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	hasRain	()Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	snowy	()Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	waterColor	(I)Lnet/minecraft/world/biome/Biome$Settings;
+transitive-accessible	method	net/minecraft/world/biome/Biome$Settings	parent	(Ljava/lang/String;)Lnet/minecraft/world/biome/Biome$Settings;
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+transitive-inject-interface	net/minecraft/world/biome/Biome$Settings	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl$SettingsExtensionImpl
+
+inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/access/BiomeAccess
diff --git a/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..a0b6d1a0
--- /dev/null
+++ b/libraries/biomes/biomes-mc16w02a-mc18w05a/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,18 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin",
+		"common.BiomeSettingsMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/build.gradle b/libraries/biomes/biomes-mc18w06a-mc18w31a/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/gradle.properties b/libraries/biomes/biomes-mc18w06a-mc18w31a/gradle.properties
new file mode 100644
index 00000000..372a4ad3
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/gradle.properties
@@ -0,0 +1,4 @@
+min_mc_version = 18w06a
+max_mc_version = 18w31a
+
+minecraft_version = 1.13
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..bc8fb566
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,91 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..c572d390
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,14 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtension {
+
+	interface BuilderExtension {
+
+		Biome.Builder parent(NamespacedIdentifier identifier);
+
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java
new file mode 100644
index 00000000..0ca2ddfc
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeIdRegistry.java
@@ -0,0 +1,20 @@
+package net.ornithemc.osl.biomes.impl;
+
+import net.minecraft.resource.Identifier;
+import net.minecraft.util.registry.IdRegistry;
+import net.minecraft.world.biome.Biome;
+
+/**
+ * The biome registry is created and populated in Biome's class initializer.
+ * This breaks OSL's usual pattern of registering the registry in the API entrypoint but
+ * triggering registry population during bootstrapping, since OSL has to wrap the Vanilla
+ * registry which is not possible without triggering Biome class load and registry
+ * population.
+ * The solution: move the Vanilla registry to another class and replace the IdRegistry
+ * reference in Biome with this one.
+ */
+public final class BiomeIdRegistry {
+
+	public static final IdRegistry<Identifier, Biome> REGISTRY = new IdRegistry<>();
+
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..c00d2e7d
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,99 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.VanillaRegistries;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = VanillaRegistries.registerSimple(RegistryKeys.BIOME, BiomeIdRegistry.REGISTRY, () -> Biome.REGISTRY);
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(identifier, biome);
+			}
+
+			return Registry.register(REGISTRY, identifier, biome);
+		}
+	}
+
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(key.identifier(), biome);
+			}
+
+			return Registry.register(REGISTRY, key, biome);
+		}
+	}
+
+	private static void registerBiomeMutation(NamespacedIdentifier identifier, Biome biome) {
+		NamespacedIdentifier parentIdentifier = biome.osl$biomes$getParentIdentifier();
+		Biome parent = REGISTRY.get(parentIdentifier);
+
+		if (parent == null) {
+			throw new IllegalStateException("Error registering mutated biome " + identifier + ": parent " + parentIdentifier + " does not exist!");
+		} else {
+			Biome.MUTATED_BIOMES.put(biome, REGISTRY.getId(parent));
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
new file mode 100644
index 00000000..e64d1669
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
@@ -0,0 +1,10 @@
+package net.ornithemc.osl.biomes.impl.access;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeAccess {
+
+	default NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		throw new AbstractMethodError();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..cf87b89b
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,17 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+
+	interface BuilderExtensionImpl extends BuilderExtension {
+
+		@Override
+		default Biome.Builder parent(NamespacedIdentifier identifier) {
+			throw new AbstractMethodError();
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
new file mode 100644
index 00000000..361f23f5
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
@@ -0,0 +1,22 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+@Mixin(Biome.Builder.class)
+public class BiomeBuilderMixin implements BiomeExtension.BuilderExtension {
+
+	@Shadow
+	public String parent;
+
+	@Override
+	public Biome.Builder parent(NamespacedIdentifier identifier) {
+		this.parent = identifier.toString();
+		return (Biome.Builder) (Object) this;
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..28719fef
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,74 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.resource.Identifier;
+import net.minecraft.util.Id2ObjectBiMap;
+import net.minecraft.util.registry.IdRegistry;
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomeIdRegistry;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.access.BiomeAccess;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.Id2ObjectBiMapMapper;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension, BiomeAccess {
+
+	@Shadow @Final
+	public static Id2ObjectBiMap<Biome> MUTATED_BIOMES;
+
+	@Shadow @Final
+	private String parent;
+
+	@Redirect(
+		method = "<clinit>",
+		at = @At(
+			value = "NEW",
+			target = "net/minecraft/util/registry/IdRegistry"
+		)
+	)
+	private static IdRegistry<Identifier, Biome> osl$biomes$replaceIdRegistry() {
+		// this allows us to register the biome registry in
+		// the API entrypoint without triggering a Biome class load
+		return BiomeIdRegistry.REGISTRY;
+	}
+
+	@Inject(
+		method = "init",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "init",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerBiomesAndMappers(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("mutated_biome"), Id2ObjectBiMapMapper.of(MUTATED_BIOMES));
+	}
+
+	@Override
+	public NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		return this.parent == null ? null : NamespacedIdentifiers.parse(this.parent);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..cb8fe0bb
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc18w06a-mc18w31a",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.13-alpha.18.6.a \u003c\u003d1.13.1-alpha.18.31.a",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..b6382d78
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,8 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(Lnet/minecraft/world/biome/Biome$Builder;)V
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+transitive-inject-interface	net/minecraft/world/biome/Biome$Builder	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl$BuilderExtensionImpl
+
+inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/access/BiomeAccess
diff --git a/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..cb076b3f
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w06a-mc18w31a/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,18 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin",
+		"common.BiomeBuilderMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/build.gradle b/libraries/biomes/biomes-mc18w32a-mc1.13.2/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/gradle.properties b/libraries/biomes/biomes-mc18w32a-mc1.13.2/gradle.properties
new file mode 100644
index 00000000..1a4324ef
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/gradle.properties
@@ -0,0 +1,4 @@
+min_mc_version = 18w32a
+max_mc_version = 1.13.2
+
+minecraft_version = 1.13.2
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..bc8fb566
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,91 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..c572d390
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,14 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtension {
+
+	interface BuilderExtension {
+
+		Biome.Builder parent(NamespacedIdentifier identifier);
+
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..43c96f8e
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,99 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.VanillaRegistries;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = VanillaRegistries.registerSimple(RegistryKeys.BIOME, net.minecraft.util.registry.Registry.BIOME);
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(identifier, biome);
+			}
+
+			return Registry.register(REGISTRY, identifier, biome);
+		}
+	}
+
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(key.identifier(), biome);
+			}
+
+			return Registry.register(REGISTRY, key, biome);
+		}
+	}
+
+	private static void registerBiomeMutation(NamespacedIdentifier identifier, Biome biome) {
+		NamespacedIdentifier parentIdentifier = biome.osl$biomes$getParentIdentifier();
+		Biome parent = REGISTRY.get(parentIdentifier);
+
+		if (parent == null) {
+			throw new IllegalStateException("Error registering mutated biome " + identifier + ": parent " + parentIdentifier + " does not exist!");
+		} else {
+			Biome.MUTATED_BIOMES.put(biome, REGISTRY.getId(parent));
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
new file mode 100644
index 00000000..e64d1669
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
@@ -0,0 +1,10 @@
+package net.ornithemc.osl.biomes.impl.access;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeAccess {
+
+	default NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		throw new AbstractMethodError();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..cf87b89b
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,17 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+
+	interface BuilderExtensionImpl extends BuilderExtension {
+
+		@Override
+		default Biome.Builder parent(NamespacedIdentifier identifier) {
+			throw new AbstractMethodError();
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
new file mode 100644
index 00000000..361f23f5
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
@@ -0,0 +1,22 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+@Mixin(Biome.Builder.class)
+public class BiomeBuilderMixin implements BiomeExtension.BuilderExtension {
+
+	@Shadow
+	public String parent;
+
+	@Override
+	public Biome.Builder parent(NamespacedIdentifier identifier) {
+		this.parent = identifier.toString();
+		return (Biome.Builder) (Object) this;
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..870452c6
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,57 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.util.Id2ObjectBiMap;
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.access.BiomeAccess;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.Id2ObjectBiMapMapper;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension, BiomeAccess {
+
+	@Shadow @Final
+	public static Id2ObjectBiMap<Biome> MUTATED_BIOMES;
+
+	@Shadow @Final
+	private String parent;
+
+	@Inject(
+		method = "init",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "init",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerBiomesAndMappers(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("mutated_biome"), Id2ObjectBiMapMapper.of(MUTATED_BIOMES));
+	}
+
+	@Override
+	public NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		return this.parent == null ? null : NamespacedIdentifiers.parse(this.parent);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..214e2bc5
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc18w32a-mc1.13.2",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.13.1-alpha.18.32.a \u003c\u003d1.13.2",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..b6382d78
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,8 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(Lnet/minecraft/world/biome/Biome$Builder;)V
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+transitive-inject-interface	net/minecraft/world/biome/Biome$Builder	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl$BuilderExtensionImpl
+
+inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/access/BiomeAccess
diff --git a/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..cb076b3f
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w32a-mc1.13.2/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,18 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin",
+		"common.BiomeBuilderMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/build.gradle b/libraries/biomes/biomes-mc18w43a-mc1.14.4/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/gradle.properties b/libraries/biomes/biomes-mc18w43a-mc1.14.4/gradle.properties
new file mode 100644
index 00000000..54620cac
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/gradle.properties
@@ -0,0 +1,4 @@
+min_mc_version = 18w43a
+max_mc_version = 1.14.4
+
+minecraft_version = 1.14.4
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..bc8fb566
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,91 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..c572d390
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,14 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtension {
+
+	interface BuilderExtension {
+
+		Biome.Builder parent(NamespacedIdentifier identifier);
+
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..43c96f8e
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,99 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.VanillaRegistries;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = VanillaRegistries.registerSimple(RegistryKeys.BIOME, net.minecraft.util.registry.Registry.BIOME);
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(identifier, biome);
+			}
+
+			return Registry.register(REGISTRY, identifier, biome);
+		}
+	}
+
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.isMutated()) {
+				registerBiomeMutation(key.identifier(), biome);
+			}
+
+			return Registry.register(REGISTRY, key, biome);
+		}
+	}
+
+	private static void registerBiomeMutation(NamespacedIdentifier identifier, Biome biome) {
+		NamespacedIdentifier parentIdentifier = biome.osl$biomes$getParentIdentifier();
+		Biome parent = REGISTRY.get(parentIdentifier);
+
+		if (parent == null) {
+			throw new IllegalStateException("Error registering mutated biome " + identifier + ": parent " + parentIdentifier + " does not exist!");
+		} else {
+			Biome.MUTATED_BIOMES.put(biome, REGISTRY.getId(parent));
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
new file mode 100644
index 00000000..e64d1669
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/access/BiomeAccess.java
@@ -0,0 +1,10 @@
+package net.ornithemc.osl.biomes.impl.access;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeAccess {
+
+	default NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		throw new AbstractMethodError();
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..cf87b89b
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,17 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+
+	interface BuilderExtensionImpl extends BuilderExtension {
+
+		@Override
+		default Biome.Builder parent(NamespacedIdentifier identifier) {
+			throw new AbstractMethodError();
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
new file mode 100644
index 00000000..361f23f5
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeBuilderMixin.java
@@ -0,0 +1,22 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+@Mixin(Biome.Builder.class)
+public class BiomeBuilderMixin implements BiomeExtension.BuilderExtension {
+
+	@Shadow
+	public String parent;
+
+	@Override
+	public Biome.Builder parent(NamespacedIdentifier identifier) {
+		this.parent = identifier.toString();
+		return (Biome.Builder) (Object) this;
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..530423b2
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,24 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.access.BiomeAccess;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension, BiomeAccess {
+
+	@Shadow @Final
+	private String parent;
+
+	@Override
+	public NamespacedIdentifier osl$biomes$getParentIdentifier() {
+		return this.parent == null ? null : NamespacedIdentifiers.parse(this.parent);
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomesMixin.java b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomesMixin.java
new file mode 100644
index 00000000..df2b51cc
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomesMixin.java
@@ -0,0 +1,41 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.world.biome.Biome;
+import net.minecraft.world.biome.Biomes;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.Id2ObjectBiMapMapper;
+
+@Mixin(Biomes.class)
+public class BiomesMixin {
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerBiomesAndMappers(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("mutated_biome"), Id2ObjectBiMapMapper.of(Biome.MUTATED_BIOMES));
+	}
+}
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..b90aa8f4
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mc18w43a-mc1.14.4",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.14-alpha.18.43.a \u003c\u003d1.14.4",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..b6382d78
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,8 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(Lnet/minecraft/world/biome/Biome$Builder;)V
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+transitive-inject-interface	net/minecraft/world/biome/Biome$Builder	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl$BuilderExtensionImpl
+
+inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/access/BiomeAccess
diff --git a/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..05d122c2
--- /dev/null
+++ b/libraries/biomes/biomes-mc18w43a-mc1.14.4/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,19 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin",
+		"common.BiomesMixin",
+		"common.BiomeBuilderMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/build.gradle b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/build.gradle
new file mode 100644
index 00000000..0a350fdb
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/build.gradle
@@ -0,0 +1 @@
+setUpModule(project)
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/gradle.properties b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/gradle.properties
new file mode 100644
index 00000000..c2b9c874
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/gradle.properties
@@ -0,0 +1,7 @@
+min_mc_version = b1.8-pre1
+max_mc_version = 1.6.4
+
+minecraft_version = 1.6.4
+raven_build = 1
+sparrow_build = 1
+nests_build = 3
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
new file mode 100644
index 00000000..0d49c6f2
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeEvents.java
@@ -0,0 +1,34 @@
+package net.ornithemc.osl.biomes.api;
+
+import net.ornithemc.osl.core.api.events.Event;
+
+/**
+ * Events related to the biomes lifecycle.
+ */
+public final class BiomeEvents {
+
+	/**
+	 * This event is invoked upon game start-up, after Vanilla biome registration is finished.
+	 * 
+	 * <p>
+	 * Custom biome registration should be done in a listener of this event.
+	 * Helper methods for registering biomes can be found in the {@linkplain
+	 * BiomeRegistry} class.
+	 * 
+	 * <p>
+	 * Listeners to this event should be registered in your mod's entrypoint,
+	 * and can be done as follows:
+	 * 
+	 * <pre>
+	 * {@code
+	 * BiomeEvents.REGISTER_BIOMES.register(() -> {
+	 * 	BiomeRegistry.register(NamespacedIdentifiers.from("example", "cookie"), new CookieBiome());
+	 * });
+	 * }
+	 * </pre>
+	 * 
+	 * @see BiomeRegistry
+	 */
+	public static final Event<Runnable> REGISTER_BIOMES = Event.runnable();
+
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
new file mode 100644
index 00000000..86e85031
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/BiomeRegistry.java
@@ -0,0 +1,106 @@
+package net.ornithemc.osl.biomes.api;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+
+/**
+ * Public access to the Biomes registry.
+ */
+public final class BiomeRegistry {
+
+	/**
+	 * @return the numerical ID assigned to the given biome.
+	 */
+	public static int getId(Biome biome) {
+		return BiomeRegistryImpl.getId(biome);
+	}
+
+	/**
+	 * @return the namespaced ID assigned to the given biome.
+	 */
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return BiomeRegistryImpl.getIdentifier(biome);
+	}
+
+	/**
+	 * @return the resource key assigned to the given biome.
+	 */
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return BiomeRegistryImpl.getKey(biome);
+	}
+
+	/**
+	 * @return the biome mapped to the given numerical ID.
+	 */
+	public static Biome getBiome(int id) {
+		return BiomeRegistryImpl.getBiome(id);
+	}
+
+	/**
+	 * @return the biome mapped to the given namespaced ID.
+	 */
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return BiomeRegistryImpl.getBiome(identifier);
+	}
+
+	/**
+	 * @return the biome mapped to the given resource key.
+	 */
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return BiomeRegistryImpl.getBiome(key);
+	}
+
+	/**
+	 * @return a set containing all namespaced IDs in the registry.
+	 */
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return BiomeRegistryImpl.identifierSet();
+	}
+
+	/**
+	 * @return a set containing all resource keys in the registry.
+	 */
+	public static Set<ResourceKey<Biome>> keySet() {
+		return BiomeRegistryImpl.keySet();
+	}
+
+	/**
+	 * @param <T>        the biome type.
+	 * @param identifier the namespaced ID of the biome.
+	 * @param biome       the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		return BiomeRegistryImpl.register(identifier, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param key   the resource key of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 */
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		return BiomeRegistryImpl.register(key, biome);
+	}
+
+	/**
+	 * @param <T>   the biome type.
+	 * @param id    the numerical ID of the biome.
+	 * @param key   the namespaced ID of the biome.
+	 * @param biome  the biome to register.
+	 * @return the registered biome.
+	 * 
+	 * @deprecated use {@linkplain #register(NamespacedIdentifier, Biome)}
+	 *             or {@linkplain #register(ResourceKey, Biome)} instead.
+	 */
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		return BiomeRegistryImpl.register(id, key, biome);
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
new file mode 100644
index 00000000..06d6a59b
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/api/biome/BiomeExtension.java
@@ -0,0 +1,13 @@
+package net.ornithemc.osl.biomes.api.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.registries.api.registry.Registry;
+
+public interface BiomeExtension {
+
+	Registry<Biome> REGISTRY = BiomeRegistryImpl.REGISTRY;
+	int AUTO_ASSIGN_ID = -172;
+
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
new file mode 100644
index 00000000..46583dba
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomeRegistryImpl.java
@@ -0,0 +1,111 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.Set;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.BiomeEvents;
+import net.ornithemc.osl.biomes.impl.biome.BiomeIdFixer;
+import net.ornithemc.osl.registries.api.registry.Registries;
+import net.ornithemc.osl.registries.api.registry.Registry;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.ResourceKey;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.impl.registry.RegistriesImpl;
+
+public final class BiomeRegistryImpl {
+
+	public static final Registry<Biome> REGISTRY = Registries.registerSimple(RegistryKeys.BIOME, () -> Biome.BY_ID.getClass());
+
+	private static boolean locked = true;
+
+	public static int getId(Biome biome) {
+		return REGISTRY.getId(biome);
+	}
+
+	public static NamespacedIdentifier getIdentifier(Biome biome) {
+		return REGISTRY.getIdentifier(biome);
+	}
+
+	public static ResourceKey<Biome> getKey(Biome biome) {
+		return REGISTRY.getKey(biome);
+	}
+
+	public static Biome getBiome(int id) {
+		return REGISTRY.get(id);
+	}
+
+	public static Biome getBiome(NamespacedIdentifier identifier) {
+		return REGISTRY.get(identifier);
+	}
+
+	public static Biome getBiome(ResourceKey<Biome> key) {
+		return REGISTRY.get(key);
+	}
+
+	public static Set<NamespacedIdentifier> identifierSet() {
+		return REGISTRY.identifierSet();
+	}
+
+	public static Set<ResourceKey<Biome>> keySet() {
+		return REGISTRY.keySet();
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(NamespacedIdentifier identifier, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, identifier, biome);
+		}
+	}
+
+	@SuppressWarnings("deprecation")
+	public static <T extends Biome> T register(ResourceKey<Biome> key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			return Registry.register(REGISTRY, biome.id, key, biome);
+		}
+	}
+
+	@Deprecated
+	public static <T extends Biome> T register(int id, NamespacedIdentifier key, T biome) {
+		if (locked) {
+			throw new IllegalStateException("register called too early: registry locked!");
+		} else {
+			if (biome.id != id) {
+				throw new IllegalArgumentException("ID " + id + " does not match biome ID " + biome.id + " for " + key);
+			}
+
+			return Registry.register(REGISTRY, id, key, biome);
+		}
+	}
+
+	public static void init() {
+		SyncedRegistries.register(RegistryKeys.BIOME);
+		SyncedRegistries.registerFixer(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/id"), new BiomeIdFixer());
+	}
+
+	public static void unlock() {
+		locked = false;
+	}
+
+	public static void registerBiomes() {
+		VanillaBiomes.init();
+		BiomeEvents.REGISTER_BIOMES.invoker().run();
+	}
+
+	public static void registerUnknownBiomes() {
+		for (Biome biome : Biome.BY_ID) {
+			if (biome != null && REGISTRY.getIdentifier(biome) == null) {
+				NamespacedIdentifier identifier = NamespacedIdentifiers.from("osl", "biome_" + biome.id);
+
+				RegistriesImpl.LOGGER.warn("Biome {}/{}", biome.id, biome.getClass().getSimpleName() + " was not registered to OSL's Biome registry! Adding it as '" + identifier + "'...");
+				BiomeRegistryImpl.register(identifier, biome);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
new file mode 100644
index 00000000..e52a2ca8
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/BiomesMixinPlugin.java
@@ -0,0 +1,45 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.util.List;
+import java.util.Set;
+
+import org.objectweb.asm.tree.ClassNode;
+
+import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
+import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
+
+public class BiomesMixinPlugin implements IMixinConfigPlugin {
+
+	public static final boolean BIOME_IDS_BEYOND_255_SUPPORTED = false;
+
+	@Override
+	public void onLoad(String mixinPackage) {
+	}
+
+	@Override
+	public String getRefMapperConfig() {
+		return null;
+	}
+
+	@Override
+	public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
+		return true;
+	}
+
+	@Override
+	public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {
+	}
+
+	@Override
+	public List<String> getMixins() {
+		return null;
+	}
+
+	@Override
+	public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+
+	@Override
+	public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
new file mode 100644
index 00000000..f8b11ddf
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/VanillaBiomes.java
@@ -0,0 +1,73 @@
+package net.ornithemc.osl.biomes.impl;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+
+public final class VanillaBiomes {
+
+	/**
+	 * Namespaced IDs were introduced in 1.9. Before then, the numerical IDs
+	 * were the only unique identifiers for biomes. Here we assign namespaced
+	 * IDs to pre-1.7 biomes, matching the 1.9 IDs  where possible.
+	 */
+	private static final String[] IDENTIFIERS = {
+		// grouped per 10 for easier lookup
+
+		"ocean",
+		"plains",
+		"desert",
+		"extreme_hills",
+		"forest",
+		"taiga",
+		"swampland",
+		"river",
+		"hell",
+		"sky",
+
+		"frozen_ocean",
+		"frozen_river",
+		"ice_flats",
+		"ice_mountains",
+		"mushroom_island",
+		"mushroom_island_shore",
+		"beaches",
+		"desert_hills",
+		"forest_hills",
+		"taiga_hills",
+
+		"smaller_extreme_hills",
+		"jungle",
+		"jungle_hills"
+	};
+
+	public static final int MAX_ID = 255;
+
+	static void init() {
+		for (Field f : Biome.class.getDeclaredFields()) {
+			if (Modifier.isStatic(f.getModifiers()) && Biome.class.isAssignableFrom(f.getType())) {
+				try {
+					Biome biome = (Biome) f.get(null);
+
+					if (biome != null) {
+						register(biome);
+					}
+				} catch (Throwable t) {
+				}
+			}
+		}
+	}
+
+	private static void register(Biome biome) {
+		if (biome.id >= 0 && biome.id < IDENTIFIERS.length) {
+			String identifier = IDENTIFIERS[biome.id];
+
+			if (identifier != null) {
+				BiomeRegistryImpl.register(NamespacedIdentifiers.from(identifier), biome);
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
new file mode 100644
index 00000000..1b77c6af
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl.java
@@ -0,0 +1,6 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+
+public interface BiomeExtensionImpl extends BiomeExtension {
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
new file mode 100644
index 00000000..1bacf15f
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/biome/BiomeIdFixer.java
@@ -0,0 +1,19 @@
+package net.ornithemc.osl.biomes.impl.biome;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.registries.api.registry.sync.IdFixer;
+
+public class BiomeIdFixer implements IdFixer {
+
+	@Override
+	public void apply() {
+		for (int id = 0; id < Biome.BY_ID.length; id++) {
+			Biome biome = Biome.BY_ID[id];
+
+			if (biome != null) {
+				biome.id = id;
+			}
+		}
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
new file mode 100644
index 00000000..763a08c6
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/java/net/ornithemc/osl/biomes/impl/mixin/common/BiomeMixin.java
@@ -0,0 +1,101 @@
+package net.ornithemc.osl.biomes.impl.mixin.common;
+
+import org.objectweb.asm.Opcodes;
+
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Mutable;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.At.Shift;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.world.biome.Biome;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
+import net.ornithemc.osl.biomes.api.biome.BiomeExtension;
+import net.ornithemc.osl.biomes.impl.BiomeRegistryImpl;
+import net.ornithemc.osl.biomes.impl.BiomesMixinPlugin;
+import net.ornithemc.osl.biomes.impl.VanillaBiomes;
+import net.ornithemc.osl.registries.api.registry.RegistryKeys;
+import net.ornithemc.osl.registries.api.registry.SyncedRegistries;
+import net.ornithemc.osl.registries.api.registry.sync.ArrayMapper;
+import net.ornithemc.osl.registries.api.registry.sync.DynamicArray;
+
+@Mixin(Biome.class)
+public class BiomeMixin implements BiomeExtension {
+
+	@Shadow @Final @Mutable
+	private static Biome[] BY_ID;
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "HEAD"
+		)
+	)
+	private static void osl$biomes$unlockBiomeRegistry(CallbackInfo ci) {
+		BiomeRegistryImpl.unlock();
+	}
+
+	@Inject(
+		method = "<clinit>",
+		at = @At(
+			value = "TAIL"
+		)
+	)
+	private static void osl$biomes$registerBiomesAndArrayMappers(CallbackInfo ci) {
+		BiomeRegistryImpl.registerBiomes();
+		BiomeRegistryImpl.registerUnknownBiomes();
+
+		SyncedRegistries.registerMapper(RegistryKeys.BIOME, NamespacedIdentifiers.from("biome/by_id"), ArrayMapper.of(() -> BY_ID, a -> BY_ID = a));
+	}
+
+	@ModifyVariable(
+		method = "<init>",
+		argsOnly = true,
+		ordinal = 0,
+		at = @At(
+			value = "INVOKE",
+			target = "Ljava/lang/Object;<init>()V",
+			shift = Shift.AFTER
+		)
+	)
+	private int osl$biomes$handleAutoAssignId(int id) {
+		if (id == AUTO_ASSIGN_ID) {
+			// the Biome[] array must contain all biomes so this should
+			// give us a valid ID for the Biome registry to use.
+			id = DynamicArray.length(BY_ID);
+
+			// keep 0-255 free for all Vanilla biomes
+			if (BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id <= VanillaBiomes.MAX_ID) {
+				id = VanillaBiomes.MAX_ID + 1;
+			}
+		}
+
+		if (!BiomesMixinPlugin.BIOME_IDS_BEYOND_255_SUPPORTED && id > VanillaBiomes.MAX_ID) {
+			throw new IllegalStateException("Biome IDs above 255 are not supported at this time!"
+					+ " Biome IDs should be limited to the range 0-255"
+					+ " unless the save format has been modified to support IDs beyond 255.");
+		}
+
+		return id;
+	}
+
+	@Inject(
+		method = "<init>",
+		at = @At(
+			value = "FIELD",
+			target = "Lnet/minecraft/world/biome/Biome;BY_ID:[Lnet/minecraft/world/biome/Biome;",
+			opcode = Opcodes.GETSTATIC,
+			args = "array=set"
+		)
+	)
+	private void osl$biomes$growArrays(int id, CallbackInfo ci) {
+		int capacity = id + 1;
+
+		BY_ID = DynamicArray.grow(BY_ID, capacity);
+	}
+}
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/fabric.mod.json b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/fabric.mod.json
new file mode 100644
index 00000000..e53ab100
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/fabric.mod.json
@@ -0,0 +1,38 @@
+{
+  "schemaVersion": 1,
+  "id": "osl-biomes",
+  "version": "0.1.0+mcb1.8-pre1-mc1.6.4",
+  "environment": "*",
+  "entrypoints": {
+    "init": [
+      "net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init"
+    ]
+  },
+  "mixins": [
+    "osl.biomes.mixins.json"
+  ],
+  "accessWidener": "osl.biomes.classtweaker",
+  "depends": {
+    "fabricloader": "\u003e\u003d0.18.0",
+    "minecraft": "\u003e\u003d1.0.0-beta.8.0.1 \u003c\u003d1.6.4",
+    "osl-core": "\u003e\u003d0.9.0",
+    "osl-entrypoints": "\u003e\u003d0.5.0",
+    "osl-lifecycle-events": "\u003e\u003d0.6.0",
+    "osl-executors": "\u003e\u003d0.1.0",
+    "osl-text-components": "\u003e\u003d0.1.0-",
+    "osl-networking": "\u003e\u003d0.10.0",
+    "osl-networking-impl": "\u003e\u003d0.2.0",
+    "osl-registries": "\u003e\u003d0.1.0"
+  },
+  "name": "OSL Biomes",
+  "description": "Biomes API and events.",
+  "authors": [
+    "OrnitheMC"
+  ],
+  "contact": {
+    "homepage": "https://ornithemc.net/",
+    "issues": "https://github.com/OrnitheMC/ornithe-standard-libraries/issues",
+    "sources": "https://github.com/OrnitheMC/ornithe-standard-libraries"
+  },
+  "license": "Apache-2.0"
+}
\ No newline at end of file
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.classtweaker b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.classtweaker
new file mode 100644
index 00000000..03b8bf50
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.classtweaker
@@ -0,0 +1,14 @@
+classTweaker	v1	named
+
+transitive-accessible	method	net/minecraft/world/biome/Biome	<init>	(I)V
+transitive-accessible	method	net/minecraft/world/biome/Biome	setTemperatureAndDownfall	(FF)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setHeight	(FF)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	disableRain	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setSnowy	()Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setName	(Ljava/lang/String;)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setMutatedColor	(I)Lnet/minecraft/world/biome/Biome;
+transitive-accessible	method	net/minecraft/world/biome/Biome	setBaseColor	(I)Lnet/minecraft/world/biome/Biome;
+
+transitive-inject-interface	net/minecraft/world/biome/Biome	net/ornithemc/osl/biomes/impl/biome/BiomeExtensionImpl
+
+mutable	field	net/minecraft/world/biome/Biome	id	I
diff --git a/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.mixins.json b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.mixins.json
new file mode 100644
index 00000000..a674432b
--- /dev/null
+++ b/libraries/biomes/biomes-mcb1.8-pre1-mc1.6.4/src/main/resources/osl.biomes.mixins.json
@@ -0,0 +1,17 @@
+{
+	"required": true,
+	"minVersion": "0.8",
+	"package": "net.ornithemc.osl.biomes.impl.mixin",
+	"compatibilityLevel": "JAVA_8",
+	"plugin": "net.ornithemc.osl.biomes.impl.BiomesMixinPlugin",
+	"mixins": [
+		"common.BiomeMixin"
+	],
+	"client": [
+	],
+	"server": [
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}
diff --git a/libraries/biomes/build.gradle b/libraries/biomes/build.gradle
new file mode 100644
index 00000000..e98ba2c6
--- /dev/null
+++ b/libraries/biomes/build.gradle
@@ -0,0 +1 @@
+setUpLibrary(project)
diff --git a/libraries/biomes/gradle.properties b/libraries/biomes/gradle.properties
new file mode 100644
index 00000000..8829b6f2
--- /dev/null
+++ b/libraries/biomes/gradle.properties
@@ -0,0 +1,7 @@
+library_id = biomes
+library_name = Biomes
+library_description = Biomes API and events.
+library_version = 0.1.0
+
+entrypoint_init = net.ornithemc.osl.biomes.impl.BiomeRegistryImpl::init
+osl_dependencies = core:0.9.0,entrypoints:0.5.0,registries:0.1.0
diff --git a/libraries/registries/registries-mc12w18a-mc1.6.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc12w18a-mc1.6.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc12w18a-mc1.6.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc12w18a-mc1.6.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc13w36a-mc14w26c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc13w36a-mc14w26c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc13w36a-mc14w26c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc13w36a-mc14w26c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc14w27a-mc17w46a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc14w27a-mc17w46a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc14w27a-mc17w46a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc14w27a-mc17w46a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc17w47a-mc18w31a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc17w47a-mc18w31a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc17w47a-mc18w31a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc17w47a-mc18w31a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc18w32a-mc1.13.2/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc18w43a-mc19w03c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc18w43a-mc19w03c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc18w43a-mc19w03c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc18w43a-mc19w03c/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mc19w04a-mc1.14.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mc19w04a-mc1.14.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mc19w04a-mc1.14.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mc19w04a-mc1.14.4/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/libraries/registries/registries-mca1.0.1_01-mc12w17a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java b/libraries/registries/registries-mca1.0.1_01-mc12w17a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
index 87d5b78a..d99f797f 100644
--- a/libraries/registries/registries-mca1.0.1_01-mc12w17a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
+++ b/libraries/registries/registries-mca1.0.1_01-mc12w17a/src/main/java/net/ornithemc/osl/registries/api/registry/RegistryKeys.java
@@ -2,6 +2,7 @@
 
 import net.minecraft.block.Block;
 import net.minecraft.item.Item;
+import net.minecraft.world.biome.Biome;
 
 import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
 import net.ornithemc.osl.core.api.util.NamespacedIdentifiers;
@@ -15,6 +16,7 @@ public final class RegistryKeys {
 
 	public static final ResourceKey<Registry<Block>> BLOCK = from("block");
 	public static final ResourceKey<Registry<Item>> ITEM = from("item");
+	public static final ResourceKey<Registry<Biome>> BIOME = from("biome");
 
 	/**
 	 * Constructs a registry key with the default namespace and the given identifier.
diff --git a/settings.gradle b/settings.gradle
index e53df069..2c30edb0 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -22,6 +22,15 @@ include ':libraries:core'
 include ':libraries:core:core-mca1.0.1_01-mc14w26c'
 include ':libraries:core:core-mc14w27a-mc1.14.4'
 
+include ':libraries:biomes'
+include ':libraries:biomes:biomes-mcb1.8-pre1-mc1.6.4'
+include ':libraries:biomes:biomes-mc13w36a-mc1.8.2-pre4'
+include ':libraries:biomes:biomes-mc1.8.2-pre5-mc15w51b'
+include ':libraries:biomes:biomes-mc16w02a-mc18w05a'
+include ':libraries:biomes:biomes-mc18w06a-mc18w31a'
+include ':libraries:biomes:biomes-mc18w32a-mc1.13.2'
+include ':libraries:biomes:biomes-mc18w43a-mc1.14.4'
+
 include ':libraries:blocks'
 include ':libraries:blocks:blocks-mca1.0.1_01-mc1.6.4'
 include ':libraries:blocks:blocks-mc13w36a-mc14w26c'