Most played cards in 4 Color Control:

2 Decks
Brainstorm
8 copies - 4 average
Ponder
8 copies - 4 average
Prismatic Ending
8 copies - 4 average
Swords to Plowshares
8 copies - 4 average
Misty Rainforest
8 copies - 4 average
Force of Will
8 copies - 4 average
Flooded Strand
8 copies - 4 average
Uro, Titan of Nature's Wrath
7 copies - 3.5 average
Carpet of Flowers
6 copies - 3 average
Minsc & Boo, Timeless Heroes
6 copies - 3 average
Endurance
5 copies - 2.5 average
Pyroblast
5 copies - 2.5 average
Life from the Loam
4 copies - 2 average
Force of Negation
4 copies - 2 average
Tropical Island
4 copies - 2 average
Narset, Parter of Veils
4 copies - 2 average
Tundra
4 copies - 2 average
Volcanic Island
3 copies - 1.5 average
Force of Vigor
3 copies - 1.5 average
Blue Elemental Blast
3 copies - 1.5 average