Most played cards in Zombies:

1 Decks
Nameless Inversion
4 copies - 4 average
Defile
4 copies - 4 average
Suffocating Fumes
4 copies - 4 average
Foul-Tongue Shriek
4 copies - 4 average
Nihil Spellbomb
4 copies - 4 average
Geth's Verdict
4 copies - 4 average
Shepherd of Rot
4 copies - 4 average
Lazotep Reaver
4 copies - 4 average
Carrion Feeder
4 copies - 4 average
Butcher Ghoul
4 copies - 4 average
Festering Mummy
4 copies - 4 average
Gempalm Polluter
4 copies - 4 average
Ghoulraiser
3 copies - 3 average
Ghoulcaller's Chant
2 copies - 2 average
Grim Physician
2 copies - 2 average