Most played cards in Crashing Footfalls:

2 Decks
Force of Negation
8 copies - 4 average
Fire // Ice
8 copies - 4 average
Mystical Dispute
8 copies - 4 average
Violent Outburst
8 copies - 4 average
Scalding Tarn
8 copies - 4 average
Brazen Borrower
8 copies - 4 average
Endurance
8 copies - 4 average
Fury
8 copies - 4 average
Shardless Agent
8 copies - 4 average
Misty Rainforest
8 copies - 4 average
Crashing Footfalls
8 copies - 4 average
Force of Vigor
8 copies - 4 average
Dead // Gone
5 copies - 2.5 average
Subtlety
5 copies - 2.5 average
Wooded Foothills
4 copies - 2 average
Bonecrusher Giant
4 copies - 2 average
Magus of the Moon
4 copies - 2 average
Steam Vents
3 copies - 1.5 average
Foundation Breaker
2 copies - 1 average
Snow-Covered Island
2 copies - 1 average