Just a quick reminder report. Here's some helpful links.

pr that's about to be merged into fabric api for standardizing c biome tag: https://github.com/FabricMC/fabric/blob/8a49467ec227b99769e984de2ead54e313303b18/fabric-convention-tags-v1/src/datagen/java/net/fabricmc/fabric/impl/tag/convention/datagen/generators/BiomeTagGenerator.java

Byg’s forge biome tags that was agreed upon between them and BoP: https://github.com/AOCAWOL/BYG/tree/1.18.X/Forge/src/main/resources/data/forge/tags/worldgen/biome

Vanilla biome tags: https://minecraft.fandom.com/wiki/Tag

Biome tags go under resources/data/<namespace>/tags/worldgen/biome