Gnomes

Gnomes are great, and I have reason for saying that. If you ever wanted an excuse to have something slightly above the medieval technology scale, gnomes were perfect. They're like the Japanese of the D&D world. Tinker Gnomes are always about a hundred years more advanced technologically than everyone else. In fact just before everyone moved away I was trying to put a game together, never got past the story stage, but the big point was that Gnomes caused a great cataclysm that wiped out their lands by pushing the boundaries of magic and technology too far. I suppose you could still use them as a story element, but I'd rather have 3rd ed. and have them playable.