I'm writing this thread to highlight a view powerful mods i had difficultys with.
These mods control spawning of mobs. I'll tell you which one is good for what.
Custom Mob Spawner, made by DrZharky. I came oacross this mod bc the Mo' Creatures Mod. (also made by DrZharky)
This mod can take control of every mob, (vanilla or mod) how often and in which biomes they should spawn.
There might be incompatiblitys with some creature mods, but i had non untill now.
Unlike the mod In Control! (which is even more powerful) the Custom Mob Spawner is easy to configure if you know where to look. In Control! is incredibly powerful. I used it to force zombies to only spawn under direct sky, so i won't have them spawn in sealed caves. You can even configuere the lootpool or equipment for mobs using this mod. However In Control! is hard to configuere imo. I was barely able to pull of that zombie setting, so i can not recommand it unless you want to force specific spawning conditions on to mobs. But i am very glad to have it.
Bad Mobs is the best pick to simply blacklist mobs.