OSE Encounter Activity Tables     Any original/official source
Pathfinder 1e Bestiary 1     Pathfinder original/official source
Scruffy Grognard's Monstrous Manual     D&D 2e (no source link)
The Monster Overhaul     OSR (no source link)
Adventures Dark And Deep     Adventures Dark And Deep (no source link)
Lairs And Encounters     Adventurer, Conqueror, King (no source link)