Most played cards in Boros Deck Wins:

5 Decks
Mogg Fanatic
20 copies - 4 average
Sacred Foundry
20 copies - 4 average
Incinerate
20 copies - 4 average
Battlefield Forge
20 copies - 4 average
Lightning Helix
19 copies - 3.8 average
Rift Bolt
19 copies - 3.8 average
Char
19 copies - 3.8 average
Honorable Passage
15 copies - 3 average
Cryoclasm
13 copies - 2.6 average
13 copies - 2.6 average
Mogg War Marshal
12 copies - 2.4 average
Magus of the Moon
11 copies - 2.2 average
Dodecapod
11 copies - 2.2 average
Greater Gargadon
11 copies - 2.2 average
Flagstones of Trokair
10 copies - 2 average
Serra Avenger
8 copies - 1.6 average
Soltari Priest
8 copies - 1.6 average
Disenchant
7 copies - 1.4 average
Seal of Fire
7 copies - 1.4 average
Siege-Gang Commander
7 copies - 1.4 average