Biome Replacer

This mod has a Neoforge 1.21 port: https://modrinth.com/mod/biome-replacer-neoforge

Small mod that replaces one biome with another, without affecting other parts of the generation. Useful for preventing certain datapack biomes from generating, fixing modded biomes not appearing, or polishing up that almost-perfect seed.

Configuration is very simple. Find biome-replacer.properties in your configuration folder, and put replacement rules in the format old_biome > new_biome. You can find some examples below.

Works fully server-side.

Note that this mod is intended mostly for replacing vanilla and datapack biomes. Biomes added using libraries like TerraBlender or Biolith cannot be replaced; you should use the mod's config to tweak or remove them instead.
That said, this mod can safely be used alongside these libraries, and it's even possible to replace vanilla/datapack biomes with modded ones.

Examples

A case with vanilla biomes. This is what configuration file looks like:

minecraft:dark_forest > minecraft:cherry_grove

And here's how the world looks, before and after:

When using Terralith, Lavender Plains biome from Aurora's Decorations won't generate. Here's how we can fix it:

terralith:lavender_forest > aurorasdeco:lavender_plains
terralith:lavender_valley > aurorasdeco:lavender_plains

Spiders are yucky. Let's remove Terralith's Infested caves:

terralith:cave/infested_caves > minecraft:dripstone_caves

Contributors

Big thanks to these cool people:

• Etos2
• LegendarySpy