Most played cards in Zoo:

2 Decks
Mortify
8 copies - 4 average
Godless Shrine
8 copies - 4 average
Overgrown Tomb
8 copies - 4 average
Putrefy
8 copies - 4 average
Rolling Spoil
4 copies - 2 average
Carven Caryatid
4 copies - 2 average
Orzhov Pontiff
4 copies - 2 average
Angel of Despair
4 copies - 2 average
Dimir Guildmage
4 copies - 2 average
Civic Wayfinder
4 copies - 2 average
Dimir Doppelganger
4 copies - 2 average
Watchwolf
4 copies - 2 average
Loxodon Hierarch
4 copies - 2 average
Dryad Sophisticate
4 copies - 2 average
Dark Confidant
4 copies - 2 average
Farseek
4 copies - 2 average
Birds of Paradise
4 copies - 2 average
Daggerclaw Imp
4 copies - 2 average
Moldervine Cloak
4 copies - 2 average
Ghost Council of Orzhova
3 copies - 1.5 average