Angry Golem (web)     D&D 5e original/official source
D&D 2e Monstrous Manual     D&D 2e (no source link)
Hacklopedia Of Beasts     Hackmaster (no source link)
Critters, Creatures, & Denizens     Dungeon Crawl Classics (no source link)
QUERP Bestiary     QUERP original/official source
Harnmaster 5e     Harnmaster (no source link)