Most played cards in U/G Control:

3 Decks
Urza's Mine
12 copies - 4 average
Simic Signet
12 copies - 4 average
Urza's Tower
12 copies - 4 average
Wall of Roots
12 copies - 4 average
Yavimaya Coast
12 copies - 4 average
Remand
12 copies - 4 average
Urza's Power Plant
12 copies - 4 average
Foresee
12 copies - 4 average
Breeding Pool
12 copies - 4 average
Spike Feeder
10 copies - 3.33 average
Chord of Calling
9 copies - 3 average
Repeal
9 copies - 3 average
Serrated Arrows
9 copies - 3 average
Vesuvan Shapeshifter
7 copies - 2.33 average
Thelonite Hermit
7 copies - 2.33 average
Mana Leak
6 copies - 2 average
Harmonize
5 copies - 1.67 average
Annex
5 copies - 1.67 average
Rewind
4 copies - 1.33 average
Willbender
4 copies - 1.33 average