Roc

Dracopedia Bestiary: An Artist's Guide     Any original/official source

The Monsters Know What They're Doing     Dungeons And Dragons original/official source

Angry Golem (web)     D&D 5e original/official source

OSE Encounter Activity Tables     Any original/official source

Pathfinder 1e Bestiary 1     Pathfinder original/official source

Pathfinder 2e Bestiary 1     Pathfinder original/official source

Mythic Monster Manual v2     Pathfinder original/official source

Monster Manual     D&D 5e original/official source

Monster Monday (web)     D&D 5e original/official source

Monster Ecology Anthology     D&D 5e (no source link)

Monster Manual     D&D 4e (no source link)

D&D 2e Monstrous Manual     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)

Hacklopedia Of Beasts     Hackmaster original/official source

Monsters Compendium     Heroes Of Adventure (no source link)

Warlords Of The Accordlands: Monsters And Lairs     d20 original/official source