I may get some flak for this, but I really like what D&D has done for / with dragons.

From (post 2nd) Kobolds and Dragonborn, to Chromatic, Metallic, Gem, and Esoteric dragons, Wyverns, Manticores, Dragonnes, Drakes, Draconians, I think there's a lot of good stuff there.

Council of Wyrms, Dragonomicon, Races of the Dragon, Dragonlance, the list goes on.

Undeniably a part of real world mythos and legends, but I think the important thing is what they've done with it. I never heard of Linnorms before D&D, though they are ostensibly Norse dragons (I haven't looked that up, but am guessing). They don't have rear legs.

Big fan of dragons, and I really like what D&D has done with them, even if that is as simple as made them more accessible to me.