This mod add many dimesions and mobs. Now MobsForMobs has 7 dimensions: Necro, Tropica, Iceland, Caveorld, BlueHell, Heaven, Dryland.
This dimensions is very hardcore. You will update your skill. Each dimension is very different from the other. They aren't boring.
Good luck!
Lickas: https://www.youtube.com/channel/UC4orZRe_kogerIALPwQe9QQ?view_as=subscriber