Pathfinder 1e Bestiary 2     Pathfinder original/official source
Pathfinder 2e Bestiary 1     Pathfinder original/official source
Tome Of Horrors Complete     Pathfinder original/official source
Mystery Monsters Revisited     Pathfinder original/official source
Forgotten Foes     Pathfinder original/official source
AD&D Fiend Folio     AD&D 1e (no source link)
Adventures Dark And Deep     Adventures Dark And Deep (no source link)