Fallout: New Vegas Creatures

Humanoid

 * Ghouls
 * Humans
 * Nightkin
 * Super mutants

Non-humanoid

 * Bighorner
 * Brahmin
 * Centaur
 * Coyote
 * Dog
 * Legion mongrel
 * Giant rat
 * Mole rat
 * Wolf

Reptiles

 * Deathclaws
 * Geckos
 * Fire gecko
 * Golden gecko
 * Little gecko
 * Mirelurk king

Creature-like plants

 * Spore plant

Unknown

 * Nightstalkers

Arthopods

 * Cazador
 * Giant ant
 * Mantis
 * Radscorpions