Most played cards in G/B Aristocrats:

4 Decks
Hissing Quagmire
16 copies - 4 average
Llanowar Wastes
16 copies - 4 average
Catacomb Sifter
16 copies - 4 average
Collected Company
16 copies - 4 average
Duskwatch Recruiter
16 copies - 4 average
Elvish Visionary
16 copies - 4 average
Zulaport Cutthroat
15 copies - 3.75 average
Westvale Abbey
13 copies - 3.25 average
Ultimate Price
13 copies - 3.25 average
Nantuko Husk
12 copies - 3 average
Cryptolith Rite
12 copies - 3 average
Transgress the Mind
12 copies - 3 average
Blisterpod
12 copies - 3 average
Matter Reshaper
7 copies - 1.75 average
Loam Dryad
7 copies - 1.75 average
Decimator of the Provinces
7 copies - 1.75 average
Reality Smasher
7 copies - 1.75 average
Languish
6 copies - 1.5 average
Liliana, Heretical Healer
5 copies - 1.25 average
Clip Wings
5 copies - 1.25 average