The Monsters Know What They're Doing     Dungeons And Dragons original/official source
Angry Golem (web)     D&D 5e original/official source
Monster Manual     D&D 5e original/official source
Volo's Guide To Monsters     D&D 5e original/official source
Monster Ecology Anthology     D&D 5e (no source link)
Monster Manual 2     D&D 4e (no source link)
Monster Manual 3     D&D 3e original/official source
Dragon Magazine Monster Ecologies     D&D 2e/3e (no source link)
MojoBob (web)     D&D 2e original/official source
D&D 2e Monstrous Manual     D&D 2e original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
AD&D Fiend Folio     AD&D 1e (no source link)