Manticoras, Hydras, Chimeras, Wyverns, Dragons, Gargoyles, Lycanthropes, Purple Worms, Sea Monsters, MinotaursThis is a good list, hitting many of the core mythological creatures that D&D has long featured. Greek and Roman myth and various diverse ancient and medieval ideas have been so thoroughly plundered that it feels downright derivative (or at best, a duplication of work) to go back to them for yet another round of inspiration. Gygax and Arneson thoroughly cemented the various monsters of heraldry and heroism into the "default" fantasy world, unfortunately almost to the level of cliché.
What I've found interesting, as anyone who's read Dungeon Crawl #1 will know, are the monsters of more recent vintage. That's a hodag in the picture, and damn if the thing - it's supposed to have lived in rural Wisconsin - doesn't look like a D&D creature. So I made it into one. (It felt particularly right since TSR, like the hodag, was from Wisconsin.) The myths of America are less well-trod and a bit weirder, since we're getting into the realms of cryptozoology and urban legends.
Living as I do in New Jersey, and having grown up in the regions that were changing from rural to suburban near Philadelphia, I went camping a lot as a kid. And when you're ten years old and sleeping out in the Pine Barrens, the Jersey Devil is the damn scariest thing in the world. You can walk by the kind of creepy old half-abandoned cabins that just seem like they could have been the birthplace of the abomination offspring of a woman and the devil, that fled out of the house as soon as it was born. Every twig snapping, even if it's just another kid going to take a leak, pings your senses and makes you certain that there's something out there in the woods. A shadow moving, even if it's the most coincidental thing, as you're gathered around the campfire sends shivers down your spine.
Fear of these monsters is fear of the unknown. It's rooted in the fact that there's something out there and you don't know what it is, but it can strike you dead in an instant. Even someone in chain mail with a sword would not relish an encounter with the Jersey Devil, or the hodag for that matter. It's a kind of horror that I think takes a subtle touch, often times more like the creepiness that you get in the X-Files than splatter horror or Cthulhuesque entities.
Really I do think there should be some element of a horror game to Dungeons & Dragons. All this time thinking about monsters has really rammed it home for me that, hey, these are monsters, any single one of which could be the subject of a horror film itself. And really it's a game about characters becoming heroic in the face of these monsters, even if the horror is primarily in the fact that so many fights end in character death.
At the same time, I want to adapt cryptids in ways that aren't overly reliant on the "solo horror monster" model that I see as working well for creatures like the Jersey Devil. There are well-worn variants, many of which have fairly popular variants: the lake monster like the Loch Ness monster or Champ in Lake Champlain, the dog-like monsters like the Chupacabra, or the humanoids like Sasquatch. I'd like to dig a little further into more types of cryptids in future entries, including their implications in play, and after that talk about the other kind of American myths, the Native American mythologies.