The Monsters Know What They're Doing     Dungeons And Dragons original/official source
Angry Golem (web)     D&D 5e original/official source
Pathfinder 1e Bestiary 1     Pathfinder original/official source
Pathfinder 2e Bestiary 1     Pathfinder original/official source
Undead Revisited     Pathfinder original/official source
Book Of Beasts: Legendary Foes     Pathfinder original/official source
Mythic Adventures     Pathfinder original/official source
Monster Manual     D&D 5e original/official source
Flee, Mortals     D&D 5e (no source link)
Monsters Of The Underworld     D&D 5e original/official source
Monster Ecology Anthology     D&D 5e (no source link)
Monster Manual     D&D 4e (no source link)
Dungeons And Dragons Essentials: Monster Vault     D&D 4e (no source link)
MojoBob (web)     D&D 2e original/official source
D&D 2e Monstrous Manual     D&D 2e (no source link)
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
AD&D Monster Manual     AD&D 1e (no source link)
13th Age Bestiary     13th Age original/official source
Dragonlance Bestiary     SAGA (no source link)
Monster Guide     World Of Warcraft RPG original/official source
Beyond The Black Sea Bestiary     Beyond The Black Sea (Dark Stars) original/official source
The Monster Overhaul     OSR (no source link)
Iron Falcon Handbook Of Monsters     OSR (no source link)