Most played cards in ATS:

5 Decks
Survival of the Fittest
20 copies - 4 average
Birds of Paradise
20 copies - 4 average
Tropical Island
20 copies - 4 average
Tradewind Rider
19 copies - 3.8 average
Brainstorm
16 copies - 3.2 average
Wall of Roots
15 copies - 3 average
Force of Will
15 copies - 3 average
Windswept Heath
13 copies - 2.6 average
Savannah
13 copies - 2.6 average
Wooded Foothills
11 copies - 2.2 average
Eternal Witness
10 copies - 2 average
Quirion Ranger
9 copies - 1.8 average
Enlightened Tutor
9 copies - 1.8 average
Taiga
9 copies - 1.8 average
Spike Feeder
8 copies - 1.6 average
Naturalize
7 copies - 1.4 average
Squee, Goblin Nabob
6 copies - 1.2 average
Flametongue Kavu
6 copies - 1.2 average
Null Rod
6 copies - 1.2 average
Absolute Law
6 copies - 1.2 average