ArPhEx: BOP Integration expands the natural spawning of ArPhEx mobs into compatible Biomes O' Plenty biomes, so now you actually find the mobs you need/want. Full list with spawn biomes for Biomes O' Plenty can be found in this google document.

This addon does not replace or modify ArPhEx's existing spawning system. Instead, it adds selected biomes from Biomes O' Plenty mod while preserving the original spawn weight, groups sizes, and spawning behavior.

Every mob can be individually configured through the config file, allowing you to enable or disable spawns in modded biomes, adjust spawn weights and groups sizes, or choose exactly which biomes each mob can appear in.

Mod contains 2 separate config files - one for overworld spawns and one for nether spawns.

The config allows for other modded biomes to be used as well, you just need to add them yourself.

Requirements:

Forge 1.20.1
ArPhEx mod
Biomes O' Plenty is not actually required (unless you want the default config which is made for BOP) as the mod works with other world generation mods as well, you just need to change the config if you're using a different mod