Most played cards in Cascade:

5 Decks
Violent Outburst
16 copies - 3.2 average
Fury
15 copies - 3 average
Simian Spirit Guide
12 copies - 2.4 average
Elvish Spirit Guide
12 copies - 2.4 average
Force of Will
12 copies - 2.4 average
Fire // Ice
12 copies - 2.4 average
Misty Rainforest
12 copies - 2.4 average
Shardless Agent
12 copies - 2.4 average
Lórien Revealed
12 copies - 2.4 average
Endurance
11 copies - 2.2 average
Wooded Foothills
10 copies - 2 average
Force of Negation
10 copies - 2 average
Force of Vigor
10 copies - 2 average
Crashing Footfalls
9 copies - 1.8 average
Brazen Borrower
9 copies - 1.8 average
Leyline of the Void
8 copies - 1.6 average
Ancient Tomb
8 copies - 1.6 average
Creative Technique
8 copies - 1.6 average
Sandstone Needle
8 copies - 1.6 average
Boseiju, Who Endures
8 copies - 1.6 average