The Monsters Know What They're Doing     Dungeons And Dragons original/official source
The Monsters Know What They're Doing 2 (moar)     Dungeons And Dragons (no source link)
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 1     Pathfinder original/official source
Monster Codex     Pathfinder original/official source
Classic Monsters Revisited     Pathfinder original/official source
Mythic Adventures     Pathfinder original/official source
Monster Manual     D&D 5e original/official source
Kobold Press Tome Of Beasts 2     D&D 5e original/official source
Flee, Mortals     D&D 5e (no source link)
Ultimate Bestiary: Revenge Of The Horde     D&D 5e original/official source
Mordenkainen's Tome Of Foes     D&D 5e original/official source
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)
Monster Manual 3     D&D 4e (no source link)
Dungeons And Dragons Essentials: Monster Vault     D&D 4e (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)
13th Age Bestiary     13th Age original/official source
Dragonlance Bestiary     SAGA (no source link)
Hacklopedia Of Beasts     Hackmaster original/official source
Critters, Creatures, & Denizens     Dungeon Crawl Classics (no source link)
Monsters Compendium     Heroes Of Adventure (no source link)
Manual Of Monsters     World Of Warcraft RPG original/official source
Old World Bestiary     Warhammer original/official source
Mystara Adversary Compendium I     Dragon Age original/official source
The Monster Overhaul     OSR (no source link)
Adventures Dark And Deep     Adventures Dark And Deep (no source link)