Most played cards in 4c Archon of Cruelty:

2 Decks
Indomitable Creativity
8 copies - 4 average
Lightning Bolt
8 copies - 4 average
Hard Evidence
8 copies - 4 average
Dwarven Mine
8 copies - 4 average
Wrenn and Six
8 copies - 4 average
Archon of Cruelty
8 copies - 4 average
Explore
7 copies - 3.5 average
Fable of the Mirror-Breaker
7 copies - 3.5 average
Scalding Tarn
7 copies - 3.5 average
Wooded Foothills
7 copies - 3.5 average
Bloodstained Mire
6 copies - 3 average
Veil of Summer
6 copies - 3 average
Prismari Command
6 copies - 3 average
Boseiju, Who Endures
5 copies - 2.5 average
Arid Mesa
5 copies - 2.5 average
Spell Pierce
5 copies - 2.5 average
Steam Vents
4 copies - 2 average
Force of Vigor
4 copies - 2 average
Mystical Dispute
4 copies - 2 average
Flusterstorm
4 copies - 2 average