Bonesinger

Bonesingers are Eldar artisans, weapon crafters, architects, masons, IT technicians, janitors, coffee brewers, firefighters, yadda yadda yadda. They possess the unique ability to shape the Wraithbone, without which the Eldar would be armless failures.

They practically never see combat, unless a Wraithlord breaks a leg or a Falcon's weapons go derp. Still, they managed to be in Dawn of War. And they managed to be OP as well. Yes, the Eldar's builder unit managed to be fucking OP in this game.