Pathfinder 1e Bestiary 2     Pathfinder original/official source
Pathfinder 2e Bestiary 2     Pathfinder original/official source
Tome Of Horrors Complete     Pathfinder original/official source
Fifth Edition Foes     D&D 5e original/official source
Encyclopedia Of Lifeforms Mundane And Magical     D&D 3e (no source link)
MojoBob (web)     D&D 2e original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
Hacklopedia Of Beasts Vol 3     Hackmaster original/official source