Pathfinder 1e Bestiary 2     Pathfinder original/official source
Pathfinder 2e Bestiary 2     Pathfinder original/official source
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