basilisk
behir
beholder
drider
cloaker
mind flayer
minotaur
purple worm
troglodytes
umber hulk




Bat, Giant Bat & Swarm of Bats
Carrion Crawler
Darkmantle
Deep Gnome (Svirfneblin)
Dinosaurs – yes they survive deep in the earth
Drow
Duergar
Fomorian
Giant Spider
Gibbering Mouther
Grick
Intellect Devourer
Hook Horror
Kobold
Myconid & Quaggoth Spore Servant
Otyugh
Piercer
Roper
Rust Monster
Spirit Naga
Violet Fungu
Xorn