Had some fun this afternoon brewing up a funky Devoid list. We're running Morophon naming Eldrazi as the commander, and the gimmick is that we only have colourless lands and everything is Devoid!
There's not much in the way of Annihilator - we're actually trying to combo off with Displacer instead and then sink either infinite ETBs or mana into some of the OGW Eldrazi to give us a win.
Reading about creature-only commander decks, now my demand avoidance is going into full overdrive and making me wonder if you could make a reasonably successful commander deck with no creatures whatsoever (e.g.: with one of the few planeswalkers that can be a commander).