Most played cards in Initiative W:

3 Decks
Chalice of the Void
12 copies - 4 average
Emeria's Call
12 copies - 4 average
Chrome Mox
12 copies - 4 average
Ancient Tomb
12 copies - 4 average
Swords to Plowshares
12 copies - 4 average
White Plume Adventurer
12 copies - 4 average
City of Traitors
12 copies - 4 average
Thalia, Guardian of Thraben
12 copies - 4 average
Cavern of Souls
11 copies - 3.67 average
Touch the Spirit Realm
11 copies - 3.67 average
Elite Spellbinder
10 copies - 3.33 average
Leyline of the Void
8 copies - 2.67 average
Solitude
8 copies - 2.67 average
Seasoned Dungeoneer
8 copies - 2.67 average
Lotus Petal
8 copies - 2.67 average
Containment Priest
6 copies - 2 average
Archon of Absolution
6 copies - 2 average
Eiganjo, Seat of the Empire
6 copies - 2 average
Walking Ballista
4 copies - 1.33 average
Palace Jailer
4 copies - 1.33 average