Pathfinder 1e Bestiary 4     Pathfinder original/official source
Tome Of Horrors Complete     Pathfinder original/official source
Tome Of Horrors 2018     D&D 5e (no source link)
Faerie Bestiary     D&D 5e (no source link)
Old Gus: Fey     D&D 5e original/official source
The Book Of The Fey     D&D 5e original/official source