Most played cards in Rogue:

2 Decks
Swords to Plowshares
8 copies - 4 average
Mishra's Factory
7 copies - 3.5 average
Disenchant
7 copies - 3.5 average
Blue Elemental Blast
5 copies - 2.5 average
Strip Mine
5 copies - 2.5 average
Shahrazad
4 copies - 2 average
Serendib Efreet
4 copies - 2 average
Energy Flux
4 copies - 2 average
Chain Lightning
4 copies - 2 average
Circle of Protection: Red
4 copies - 2 average
Lightning Bolt
4 copies - 2 average
Plateau
4 copies - 2 average
Savannah Lions
4 copies - 2 average
Dust to Dust
4 copies - 2 average
Tundra
4 copies - 2 average
Power Sink
3 copies - 1.5 average
Avoid Fate
3 copies - 1.5 average
Tropical Island
3 copies - 1.5 average
Psionic Blast
3 copies - 1.5 average
Volcanic Island
3 copies - 1.5 average