Quartz
Hero
Thoughts? Basic idea is the elves eliminated themselves and the PCs have to rediscover the Drow assuming I use them.
This is also in Dragonlance, only it was the ogres who eliminated themselves, devolving into cruder forms, with the remaining good ones (the Irda) fleeing to a hidden isle.
But I too dig the Valheru. You could perhaps have them as warlock patrons, as Ashen-Shugar was to Tomas.