Most played cards in Sygg, River Cutthroat:

3 Decks
Force Spike
3 copies - 1 average
Undermine
3 copies - 1 average
Vendilion Clique
3 copies - 1 average
Flooded Strand
3 copies - 1 average
Remand
3 copies - 1 average
Underground Sea
3 copies - 1 average
Mutavault
3 copies - 1 average
Vapor Snag
3 copies - 1 average
Cyclonic Rift
3 copies - 1 average
Mox Diamond
3 copies - 1 average
Snapcaster Mage
3 copies - 1 average
Inkfathom Infiltrator
3 copies - 1 average
Lotus Petal
3 copies - 1 average
Delver of Secrets
3 copies - 1 average
Force of Will
3 copies - 1 average
True-Name Nemesis
3 copies - 1 average
Bonesplitter
3 copies - 1 average
Faerie Conclave
3 copies - 1 average
Counterspell
3 copies - 1 average
Watery Grave
3 copies - 1 average