The Monsters Know What They're Doing     Dungeons And Dragons original/official source
The Monsters Know What They're Doing 2 (moar)     Dungeons And Dragons (no source link)
Creature Chronicle (web)     Pathfinder original/official source
Monster Manual     D&D 5e original/official source
Monster Manual Expanded v1     D&D 5e original/official source
Monster Manual Expanded v2     D&D 5e original/official source
Volo's Guide To Monsters     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)
Monster Manual 3     D&D 4e original/official source
Dungeons And Dragons Essentials: Monster Vault     D&D 4e (no source link)
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)