Most played cards in U/W Control:

1 Decks
Reflecting Pool
4 copies - 4 average
Path to Exile
4 copies - 4 average
Mutavault
4 copies - 4 average
Telling Time
4 copies - 4 average
Burrenton Forge-Tender
4 copies - 4 average
Kitchen Finks
4 copies - 4 average
Celestial Purge
4 copies - 4 average
Mulldrifter
4 copies - 4 average
Mystic Gate
4 copies - 4 average
Cryptic Command
4 copies - 4 average
Broken Ambitions
4 copies - 4 average
Adarkar Wastes
4 copies - 4 average
Elspeth, Knight-Errant
3 copies - 3 average
Remove Soul
3 copies - 3 average
Forbidding Watchtower
3 copies - 3 average
Negate
3 copies - 3 average
Flashfreeze
3 copies - 3 average
Wrath of God
3 copies - 3 average
Oblivion Ring
2 copies - 2 average
Faerie Conclave
1 copies - 1 average