Most played cards in U/B Control:

1 Decks
Recoil
4 copies - 4 average
Polluted Delta
4 copies - 4 average
Smother
4 copies - 4 average
Mesmeric Fiend
4 copies - 4 average
Underground River
4 copies - 4 average
Engineered Plague
4 copies - 4 average
Shadowmage Infiltrator
4 copies - 4 average
Cabal Therapy
4 copies - 4 average
Braids, Cabal Minion
4 copies - 4 average
Dark Confidant
4 copies - 4 average
Chainer's Edict
4 copies - 4 average
Chrome Mox
4 copies - 4 average
Duress
3 copies - 3 average
Annul
3 copies - 3 average
Pithing Needle
3 copies - 3 average
Withered Wretch
2 copies - 2 average
Sword of Fire and Ice
2 copies - 2 average
Sensei's Divining Top
2 copies - 2 average
Tomb of Urami
1 copies - 1 average
Shizo, Death's Storehouse
1 copies - 1 average