Nether Biomes

Shadow Forests
Spawns: Wither and Non Wither Skeleton, Floating Skulls

Mysterious Forests
Spawns: Peaceful animals and House and Tree Creepers

Petrified Abyssals
Spawns: Silbat, Ravagers, scorpion, silverfish and iron ore bug

Obsidian Plains
Spawns: Mimics

Blazing Terras
Spawns: Blazes