Most played cards in The Rock:

4 Decks
Birds of Paradise
16 copies - 4 average
Duress
16 copies - 4 average
Pernicious Deed
16 copies - 4 average
Llanowar Wastes
15 copies - 3.75 average
Cabal Therapy
14 copies - 3.5 average
Treetop Village
12 copies - 3 average
Spiritmonger
11 copies - 2.75 average
Ravenous Baloth
11 copies - 2.75 average
Wall of Blossoms
8 copies - 2 average
Windswept Heath
7 copies - 1.75 average
Yavimaya Elder
7 copies - 1.75 average
Spike Feeder
7 copies - 1.75 average
Living Wish
7 copies - 1.75 average
Diabolic Edict
7 copies - 1.75 average
Smother
6 copies - 1.5 average
Haunting Echoes
5 copies - 1.25 average
Engineered Plague
5 copies - 1.25 average
Call of the Herd
4 copies - 1 average
Tranquil Thicket
4 copies - 1 average
Vindicate
4 copies - 1 average