Druid, drood, dr00d, durid, bear, bare, rawr, cat, kitty, feral, tree, trees, tree mafia, moonkin, boomkin, oomkin, featherkin, panzerkin, owlbear, doomkin, seal, manatee, cheetah, travel, caster, humanoid, spamfire, bees, dreamstate, OP, balance, boomy, resto, laser chicken, feathers, KFC...
Wow, druids have a lot of monikers. I don't even know them all, probably. What's interesting is there are more for Moonkins than any other druid spec, and it's the most underutilized!
Did I miss any? Can you think of any more?
Added by others:
space turkey - Phaelia
laser pigeon - anonymous
restro - nilianil