Most played cards in 8 Cast:

2 Decks
Urza's Saga
8 copies - 4 average
Force of Will
8 copies - 4 average
Chalice of the Void
8 copies - 4 average
Lotus Petal
8 copies - 4 average
Seat of the Synod
8 copies - 4 average
Mox Opal
8 copies - 4 average
Ancient Tomb
8 copies - 4 average
Force of Negation
8 copies - 4 average
Thought Monitor
7 copies - 3.5 average
Urza's Bauble
4 copies - 2 average
Cavern of Souls
4 copies - 2 average
Karn, the Great Creator
4 copies - 2 average
Sai, Master Thopterist
4 copies - 2 average
Swords to Plowshares
4 copies - 2 average
Emry, Lurker of the Loch
4 copies - 2 average
Mishra's Bauble
4 copies - 2 average
Tundra
4 copies - 2 average
Ingenious Smith
4 copies - 2 average
Urza, Lord High Artificer
4 copies - 2 average
Esper Sentinel
4 copies - 2 average