Dracopedia Bestiary: An Artist's Guide     Any original/official source
Atlas Animalia     Any original/official source
Pathfinder 1e Bestiary 2     Pathfinder original/official source
Pathfinder 2e Bestiary 2     Pathfinder original/official source
Cerulean Seas: Beasts Of The Boundless Blue     Pathfinder original/official source
Tome Of Horrors Complete     Pathfinder original/official source
Forgotten Foes     Pathfinder original/official source
Dragon Magazine     D&D 2e/3e (no source link)
MojoBob (web)     D&D 2e original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
AD&D Monster Manual     AD&D 1e (no source link)
Dragonlance Bestiary     SAGA (no source link)
Adventures Dark And Deep     Adventures Dark And Deep (no source link)
Baby Bestiary 1     Any original/official source