The Monsters Know What They're Doing     Dungeons And Dragons original/official source
Monstrosities     Swords & Wizardry original/official source
Angry Golem (web)     D&D 5e original/official source
OSE Encounter Activity Tables     Any original/official source
Pathfinder 1e Bestiary 1     Pathfinder original/official source
Pathfinder 2e Bestiary 2     Pathfinder original/official source
Classic Horrors Revisited     Pathfinder original/official source
Exotic Encounters     Pathfinder original/official source
Mythic Adventures     Pathfinder original/official source
Tome Of Horrors 2020     D&D 5e original/official source
Flee, Mortals     D&D 5e (no source link)
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)
Dragon Magazine     D&D 2e/3e (no source link)
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)
Dragonlance Bestiary     SAGA (no source link)
Hacklopedia Of Beasts Vol 5     Hackmaster original/official source
Monsters Compendium     Heroes Of Adventure (no source link)
Mystara Adversary Compendium I     Dragon Age original/official source
Monsters And Treasure (2019)     Castles And Crusades original/official source
The Monster Overhaul     OSR (no source link)
Adventures Dark And Deep     Adventures Dark And Deep (no source link)
Abnormal Undead     Any original/official source