Most played cards in Quicksilver:

2 Decks
Serendib Efreet
8 copies - 4 average
Chain Lightning
8 copies - 4 average
Lightning Bolt
8 copies - 4 average
Taiga
8 copies - 4 average
Kird Ape
8 copies - 4 average
Mishra's Factory
8 copies - 4 average
City of Brass
7 copies - 3.5 average
Psionic Blast
7 copies - 3.5 average
Tropical Island
7 copies - 3.5 average
Nevinyrral's Disk
7 copies - 3.5 average
Volcanic Island
7 copies - 3.5 average
Red Elemental Blast
7 copies - 3.5 average
Erhnam Djinn
7 copies - 3.5 average
Blue Elemental Blast
4 copies - 2 average
Fireball
4 copies - 2 average
Shatter
3 copies - 1.5 average
Control Magic
3 copies - 1.5 average
Earthquake
3 copies - 1.5 average
Power Sink
3 copies - 1.5 average
Timetwister
2 copies - 1 average