Most played cards in Survival:

3 Decks
Survival of the Fittest
12 copies - 4 average
Vengevine
6 copies - 2 average
Misty Rainforest
6 copies - 2 average
Basking Rootwalla
5 copies - 1.67 average
Taiga
5 copies - 1.67 average
Mental Misstep
5 copies - 1.67 average
Force of Will
4 copies - 1.33 average
Phyrexian Dreadnought
4 copies - 1.33 average
Nature's Claim
4 copies - 1.33 average
Bayou
4 copies - 1.33 average
Dark Confidant
4 copies - 1.33 average
Thoughtseize
4 copies - 1.33 average
Grafdigger's Cage
4 copies - 1.33 average
Abrupt Decay
4 copies - 1.33 average
Cavern of Souls
4 copies - 1.33 average
Mishra's Workshop
4 copies - 1.33 average
Goblin Welder
4 copies - 1.33 average
Wooded Foothills
4 copies - 1.33 average
Tropical Island
4 copies - 1.33 average
Red Elemental Blast
3 copies - 1 average