Most played cards in Shops:

1 Decks
Mishra's Workshop
4 copies - 4 average
Urza's Saga
4 copies - 4 average
Wasteland
4 copies - 4 average
Ancient Tomb
4 copies - 4 average
Sphere of Resistance
4 copies - 4 average
Walking Ballista
4 copies - 4 average
Foundry Inspector
4 copies - 4 average
Nettlecyst
4 copies - 4 average
Phyrexian Revoker
4 copies - 4 average
Arcbound Ravager
4 copies - 4 average
Grafdigger's Cage
3 copies - 3 average
Ravenous Trap
3 copies - 3 average
Wurmcoil Engine
2 copies - 2 average
Soul-Guide Lantern
2 copies - 2 average
Mindbreak Trap
2 copies - 2 average
Trinisphere
1 copies - 1 average
Karn, Scion of Urza
1 copies - 1 average
Skysovereign, Consul Flagship
1 copies - 1 average
Karn, the Great Creator
1 copies - 1 average
Thorn of Amethyst
1 copies - 1 average