Most played cards in 8 Cast:

1 Decks
Seat of the Synod
4 copies - 4 average
Thoughtcast
4 copies - 4 average
Force of Will
4 copies - 4 average
Flusterstorm
4 copies - 4 average
Urza's Saga
4 copies - 4 average
Thought Monitor
4 copies - 4 average
Hurkyl's Recall
4 copies - 4 average
Soul-Guide Lantern
3 copies - 3 average
Pithing Needle
3 copies - 3 average
Mox Opal
3 copies - 3 average
Emry, Lurker of the Loch
3 copies - 3 average
Mishra's Bauble
2 copies - 2 average
Urza, Lord High Artificer
2 copies - 2 average
Mystical Dispute
2 copies - 2 average
Dismember
2 copies - 2 average
Urza's Bauble
2 copies - 2 average
Time Walk
1 copies - 1 average
Snow-Covered Island
1 copies - 1 average
Sea Gate Restoration
1 copies - 1 average
Grafdigger's Cage
1 copies - 1 average