Important

I used to think the name lich should be entirely replaced with "skeletor" but actually , no that's terrible. I mean anytime you think of using a lich you should just use Skeletor , but no liches should not be called skeletor's that's ridiculous .
HOWEVER I RECOMMEND THE FOLLOWING NOMENCLATURE

Aerial servant : Cloud Goon
Anhkheg:  Hate-Mole
Beetle, giant : Insector Rex
Black pudding : The Chubber
Blink dog : Time Wolf
Brownie : Gomorrite
Bugbear : Shaggy Badtimes
Bulette : Dirt-Shark
Carrion crawler: Corpse-Sucker
Centaur : Manhorse

Cloaker: MkUltra
Couatl : Secret Serpent
Dragon : Horse
Dragonne : Suck-Beast
Dragon turtle : Gamera
Ear seeker : Brain Worm
Eye, floating : Scream Eye
Eye of the deep : Drowning Bell
Fungi, violet : Tubscelant Rotter
Gas spore : Exploder
Ghast : Sicker
Ghost: Space-Vomit
Giant : Daddy
Gnoll: Superdog
Gnome : Knob
Goblins: Tickleboys
Gorgon : Ambombibull
Gray ooze :Slunk
Green slime :  Prasinous Illness
Griffon : Mess-Bird
Halfling : Manlet
Hippocampus : Sea-Pony
Hippogriff : Donkey-Bird
Hobgoblin : Henrys
Horse : Lobotomized Brute
Intellect devourer : Escaped Brain
Invisible stalker : Secret Murderer
Irish deer : Hell-Moose
Ixitxachitl : Bastard of The Sea, Sea Bastard
Jackalwere : Garbage-Dog
Ki-rin : Elder-Dog
Kobold : Daniels
Lamia : She-Beast
Lammasu : MellowLord
Lizard man : Plutonian
Locathah : War-Fish
Lurker above : False- Ceiling
Masher: Knife-cod
Merman : Mermaid
Mind flayer : never use illithid "illithid is their name for themselves" no-one cares about their feelings, we don't have to learn this word, don't try and make these dollarstore lovecrafts seem Eldritch or whatever. They are man with a squid for a head that eats brains , that is both the description and bio of a toy a kid made by glueing their toys together, it's great 
Mold : Beard
Morkoth : Hynosquid
Neo-otyugh: Poop-Bluto
Nixie : Shellycoats
Ochre Jelly: Danger-Goo
Ogre : Bethany
Ogre mage(Japanese ogre) : Bethany-Chan
Orc : Sly-Simons
Otyugh: Poop-Popeye
Owlbear: Trash-Beast

Pegasus : Power-Elf
Peryton : Pain-Deer
Piercer : Stalagfight
Pixie : Sodomite
Portuguese man-o-war, giant : Tentacruel
Pseudo-dragon : Peep-Peep
Purple worm: Conquerer Worm
Quasit : Bad Idea Brian
Roper : these are a mess anyway CaveCops (thanks Nick)
Rust monster : Wrickets
Sahuagin: Sharkanoid
Satyr : Mangoat
Sea lion: Ocean-Savager
Shedu : Dude
Shrieker: Unfungus
Skeleton : Skeleton
Slithering tracker : Sucking Chyle
Spectre : GodSick
Sprite : Catamite
Stirge : Needler
Strangle weed: KillWeed
Su-monster : Brain-Ape
Sylph :SkyVixen
Titan : Ultra-Masc
Trapper: Unwelcome Mat
Treant : Thug-Tree
Triton : Aquaman
Troglodyte : Piss-Newt
Unicorn : Ponylord
Vampire : Batman
Water weird : Ghost-Snake
Will-o-(the)-wisp : Blights
Wyvern: Ultra-Vulture
Xorn : Dirt-Ghost
Zombie: Smelly Doug