Most played cards in UWR Control:

4 Decks
Flooded Strand
16 copies - 4 average
Snapcaster Mage
16 copies - 4 average
Scalding Tarn
15 copies - 3.75 average
Path to Exile
15 copies - 3.75 average
Serum Visions
15 copies - 3.75 average
Lightning Bolt
13 copies - 3.25 average
Lightning Helix
13 copies - 3.25 average
Cryptic Command
13 copies - 3.25 average
Celestial Colonnade
12 copies - 3 average
Search for Azcanta
8 copies - 2 average
Hallowed Fountain
8 copies - 2 average
Steam Vents
8 copies - 2 average
Electrolyze
7 copies - 1.75 average
Celestial Purge
6 copies - 1.5 average
Supreme Verdict
6 copies - 1.5 average
Logic Knot
6 copies - 1.5 average
Negate
6 copies - 1.5 average
Dispel
5 copies - 1.25 average
Wear // Tear
5 copies - 1.25 average
Damping Sphere
5 copies - 1.25 average