Pathfinder 1e Bestiary 2     Pathfinder original/official source
Forgotten Foes     Pathfinder original/official source
Faerie Bestiary     D&D 5e (no source link)
Monsters Of Feyland     D&D 5e original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
QUERP Bestiary     QUERP original/official source