I have byg and bop installed and many of the mobs don't spawn in them or at all for that matter. I have never seen platypus, frostwalkers, tusklins, kommodo dragon, shrimp, blobfish, sugar gliders, orca, snow leopards, or soul vultures just to name a few of them.

I have deleted the config file with all of their biome spawns and the server has never been updated. Are there any fixes for this?

I added this to All The Mods 8, all I've seen so far is a single fly... was coming here in hopes of finding answers as to why nothing is spawning, but it seems I'm not the only one with the problem. Hope someone finally gets to answering this one!