Most played cards in Zoo:

1 Decks
Lightning Helix
4 copies - 4 average
Kird Ape
4 copies - 4 average
Molten Rain
4 copies - 4 average
Tarmogoyf
4 copies - 4 average
Samurai of the Pale Curtain
4 copies - 4 average
Windswept Heath
4 copies - 4 average
Grim Lavamancer
4 copies - 4 average
Sacred Foundry
4 copies - 4 average
Goblin Legionnaire
4 copies - 4 average
Kataki, War's Wage
3 copies - 3 average
Isamaru, Hound of Konda
3 copies - 3 average
Char
3 copies - 3 average
Savannah Lions
3 copies - 3 average
Orim's Chant
3 copies - 3 average
Sulfuric Vortex
3 copies - 3 average
Wooded Foothills
3 copies - 3 average
Firebolt
3 copies - 3 average
Lava Dart
3 copies - 3 average
Disenchant
2 copies - 2 average
Stomping Ground
2 copies - 2 average