I would like to argue Electivire for C-Rank or higher. Vire's very appealing ability Motor Drive multiplies it's speed by 1.5 times, the same boost a scarf gives you, if I'm not mistaken. This allows it to gain speed even on a band set, which is appealing given the fact that it has a huse base Attack stat and great coverage across the board. Even on non Band sets this brings a whole new dimension to offensive options, and brings Vire to a position of a frighteningly powerful sweeper.
<Scarfwynaut> can't people just sit around and eat a cheese wheel?
<Scarfwynaut> that is my kind of social gathering