Monstrosities     Swords & Wizardry original/official source
Angry Golem (web)     D&D 5e original/official source
Pathfinder 1e Bestiary 1     Pathfinder original/official source
Monster Manual 2     D&D 4e (no source link)
Critter Cache: Animals And Beasts     D&D 4e original/official source
MojoBob (web)     D&D 2e original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
Hacklopedia Of Beasts     Hackmaster original/official source
Hacklopedia Of Beasts Vol 1     Hackmaster original/official source
QUERP Bestiary     QUERP original/official source
Mystara Adversary Compendium I     Dragon Age original/official source
Adventures Dark And Deep     Adventures Dark And Deep (no source link)
Lairs And Encounters     Adventurer, Conqueror, King (no source link)