Most played cards in Survival:

2 Decks
Vengevine
8 copies - 4 average
Basking Rootwalla
8 copies - 4 average
Bazaar of Baghdad
8 copies - 4 average
Hollow One
8 copies - 4 average
Survival of the Fittest
8 copies - 4 average
Ravenous Trap
6 copies - 3 average
Savannah
5 copies - 2.5 average
Misty Rainforest
5 copies - 2.5 average
Thalia, Guardian of Thraben
5 copies - 2.5 average
Energy Flux
5 copies - 2.5 average
Stony Silence
5 copies - 2.5 average
Noble Hierarch
4 copies - 2 average
Tropical Island
4 copies - 2 average
Verdant Catacombs
4 copies - 2 average
Elvish Spirit Guide
4 copies - 2 average
Containment Priest
4 copies - 2 average
Nature's Claim
3 copies - 1.5 average
Squee, Goblin Nabob
3 copies - 1.5 average
Manglehorn
3 copies - 1.5 average
Tarmogoyf
3 copies - 1.5 average