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 (no source link)
Monster Codex     Pathfinder original/official source
Darklands Revisited     Pathfinder original/official source
All Sorts Of Critters (web)     Pathfinder original/official source
Monster Manual     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 2     D&D 4e (no source link)
Dungeons And Dragons Essentials: Monster Vault     D&D 4e (no source link)
D&D 2e Monstrous Manual     D&D 2e (no source link)
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
AD&D Monster Manual     AD&D 1e (no source link)
13th Age Bestiary 2     13th Age (no source link)
Hacklopedia Of Beasts     Hackmaster original/official source
Baby Bestiary 2     Any original/official source