All Monsters (19)

• 13 HD Monsters in Basic Fantasy Field Guide Omnibus
  
• 13 HD Monsters in Basic Fantasy Role-Playing Game
  
• 13 HD Monsters in Old-School Essentials Advanced Fantasy Genre Rules
  
• 13 HD Monsters in Old-School Essentials Classic Fantasy
  
• 13 HD Monsters in OSRIC
  
• Aergian Amalgamation - A violent creature formed from failed adventurers' souls, resembling four monstrous hands with six tentacle-like appendages
  Field Guide
• Behir - A serpentine monster with a dozen legs that can slither like a snake or move with considerable speed
  Field Guide, OSRIC
• Cyclops - 20' tall humanoids with a single, central eye
  OSE, OSRIC
• Dinosaur, Gorgosaurus - A bipedal carnivorous theropod dinosaur, close relative to tyrannosaurus rex
  Field Guide
• Dragon Turtle - Massive aquatic creatures up to 200 feet long, occasionally mistaken for rocky outcroppings or small islands
  BFRPG, OSE, OSRIC
• Eye of the Deep - Globular aquatic monster with a massive central eye, two eyestalks, lobster-like pincers, and a gaping maw
  OSE-AF, OSRIC
• Giant, Cyclops - A one-eyed giant, huge and brutish, resembling hill giants
  BFRPG
• Giant, Ettin - A vicious and unpredictable 2-headed giant with thick, gray hide
  Field Guide
• Giant, Sand - Dark-skinned, hairy giants with black hair and blue eyes who dress in flowing white robes
  Field Guide
• Golem, Gold - Ostentatious womanly-shaped construct made of animated gold
  Field Guide
• Infernal, Fiend - A large masculine humanoid devil with bat-like wings, appearing wreathed in flames
  Field Guide
• Mammoth - Huge, shaggy prehistoric relatives of the elephant
  BFRPG, OSRIC
• Pit Fiend - Personal servants of Asmodeus, native to the 9th Plane of Hell
  OSRIC
• Shambler - An intelligent carnivorous plant that appears as a heap of rotting vegetation
  Field Guide