The Monsters & Creatures Compendium     Any (no source link)
Monstrosities     Swords & Wizardry 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
Mythic Monster Manual v1     Pathfinder original/official source
Dragons Revisited     Pathfinder original/official source
Codex Draconis     Pathfinder original/official source
Mythic Adventures     Pathfinder original/official source
Monster Manual     D&D 5e original/official source
Fizban's Treasury Of Dragons     D&D 5e original/official source
Monster Ecology Anthology     D&D 5e (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)
Hacklopedia Of Beasts Vol 2     Hackmaster original/official source