Most played cards in The Rock:

3 Decks
Bayou
12 copies - 4 average
Mishra's Factory
11 copies - 3.67 average
Argothian Pixies
9 copies - 3 average
Hypnotic Specter
8 copies - 2.67 average
Crumble
8 copies - 2.67 average
City of Brass
8 copies - 2.67 average
Juzám Djinn
7 copies - 2.33 average
Avoid Fate
7 copies - 2.33 average
Erhnam Djinn
7 copies - 2.33 average
Paralyze
7 copies - 2.33 average
Whirling Dervish
6 copies - 2 average
Sylvan Library
6 copies - 2 average
Gloom
5 copies - 1.67 average
Strip Mine
5 copies - 1.67 average
Tropical Island
4 copies - 1.33 average
Elves of Deep Shadow
4 copies - 1.33 average
Disenchant
4 copies - 1.33 average
Terror
4 copies - 1.33 average
Swords to Plowshares
4 copies - 1.33 average
Sinkhole
4 copies - 1.33 average