Trogdor may be a man, a dragon-man, or maybe he's just a dragon. (The confusion probably arises from the "big beefy arm" he has coming out of his back.)
But he's still TROGDOOOOOOOOOOOOR!
There's also a dragon that makes it's territory in the general area of the King of Town's castle (or, it did. It hasn't appeared since the Knight accidentally set it to "instant death" instead of "sanitize", so it might still be dead) that appears to be equal parts lizard and kangaroo, with a little bit of deer and bug mixed in for flavor.
Cody from DSBT InsaniT supposedly has command over a dragon made of crystal.
Matt N Dusty has a big pink wingless dragon that bakes cookies. She's also the most adorable thing on the show so far.