I really, really want a whole lot more evil Wood Elves and High Elves-- and maybe just aspects of their cultures that just edge on evil and easily become slippery slopes for them to become villains.
As mentioned earlier, read the Mazalan Book of the Fallen. Specifically the Tiste Liosan - the "light elves", the children of the light. They are so "good" that they are effectively villains. Unfortunately they are not a major protagonist.