Most played cards in Chromium, the Mutable:

2 Decks
Demonic Tutor
2 copies - 1 average
Cryptic Command
2 copies - 1 average
Counterspell
2 copies - 1 average
Disallow
2 copies - 1 average
Dismiss
2 copies - 1 average
Fact or Fiction
2 copies - 1 average
Condescend
2 copies - 1 average
Dromar's Charm
2 copies - 1 average
Condemn
2 copies - 1 average
Torrential Gearhulk
2 copies - 1 average
Snapcaster Mage
2 copies - 1 average
Baleful Strix
2 copies - 1 average
Wall of Omens
2 copies - 1 average
Absorb
2 copies - 1 average
Collective Brutality
2 copies - 1 average
Blessed Alliance
2 copies - 1 average
Balance
2 copies - 1 average
Force of Will
2 copies - 1 average
Gerrard's Verdict
2 copies - 1 average
Vindicate
2 copies - 1 average