All Monsters (21)

• 15 HD Monsters in Basic Fantasy Field Guide Omnibus
  
• 15 HD Monsters in Basic Fantasy Role-Playing Game
  
• 15 HD Monsters in Old-School Essentials Advanced Fantasy Genre Rules
  
• 15 HD Monsters in Old-School Essentials Classic Fantasy
  
• 15 HD Monsters in OSRIC
  
• Bear, Ursine Behemoth - A rare bear of truly gargantuan size, 20 to 30 feet tall when standing upright
  Field Guide
• Dinosaur, Allosaurus - A swift-running bipedal carnivorous dinosaur, slightly more than 30 feet long
  Field Guide
• Dinosaur, Elasmosaurus - A prehistoric aquatic reptile with a flat body, short tail, and long neck
  Field Guide
• Djinni (Greater)
  OSE-AF
• Edmontosaurus - Cretaceous herbivore, formerly "anatosaurus"
  OSRIC
• Giant Crocodile - More than 50' long crocodile that will attack small ships
  OSE, OSRIC
• Giant Sea Turtle - Massive beasts, normally placid but ferocious when they feel they are under attack
  OSRIC
• Giant, Storm - Adult storm giants are about 21 feet tall and weigh about 12,000 pounds
  BFRPG
• Gorgosaurus - Cretaceous carnivore, smaller than tyrannosaurus
  OSRIC
• Mammoth - Huge, shaggy prehistoric relatives of the elephant
  BFRPG, OSRIC
• Mastodon - Intelligent, aggressive prehistoric relatives of the elephant
  BFRPG, OSE, OSRIC
• Purple Worm - Gigantic subterranean monsters with poisonous stingers
  BFRPG, OSE, OSRIC
• Sea Turtle
  OSE-AF
• Shield Guardian - A 9-foot tall magical construct that protects its master through a linked amulet
  Field Guide
• Storm Giant - 22' tall humanoids with bronze-hued skin and garish hair (red or yellow)
  OSE, OSRIC
• Turtle, Giant Sea - Shy creatures with powerful armor and a devastating bite that can swallow prey whole
  Field Guide