Getting a crash with this mod: https://paste.dimdev.org/jucoyexaje.mccrash

Full mod list: https://paste.dimdev.org/uhomuwipur.md

Forge 2836
stygian-1.0.4

Invalid id 256 - maximum id range exceeded.
You've simply got too many biomes in your pack, there's a limit of 256. Some mods try to remove this limit but they are kind of hit or miss in their effectiveness.

Nope...played with way more biomes than this. That's what Not Enough IDs is for.

Notenoughids extends the block ID limit, not biomes. Maybe you're thinking of justenoughids (gotta love these names)