Most played cards in Red Deck Wins:

2 Decks
Magus of the Moon
8 copies - 4 average
Price of Progress
8 copies - 4 average
Lightning Bolt
8 copies - 4 average
Simian Spirit Guide
8 copies - 4 average
Tormod's Crypt
7 copies - 3.5 average
Fireblast
7 copies - 3.5 average
Pyroblast
7 copies - 3.5 average
Shattering Spree
6 copies - 3 average
Pyrostatic Pillar
6 copies - 3 average
Gorilla Shaman
6 copies - 3 average
Black Vise
4 copies - 2 average
Ankh of Mishra
4 copies - 2 average
Grim Lavamancer
4 copies - 2 average
Mogg Fanatic
4 copies - 2 average
Fractured Loyalty
4 copies - 2 average
3 copies - 1.5 average
Viashino Heretic
3 copies - 1.5 average
Word of Seizing
2 copies - 1 average
Countryside Crusher
2 copies - 1 average
Red Elemental Blast
2 copies - 1 average