Most played cards in Grixis Control:

1 Decks
Abrade
4 copies - 4 average
Fetid Pools
4 copies - 4 average
Essence Scatter
4 copies - 4 average
Harnessed Lightning
4 copies - 4 average
Negate
4 copies - 4 average
Vraska's Contempt
4 copies - 4 average
Aether Hub
4 copies - 4 average
Spirebluff Canal
4 copies - 4 average
Whirler Virtuoso
4 copies - 4 average
Glint-Sleeve Siphoner
4 copies - 4 average
Fatal Push
3 copies - 3 average
Canyon Slough
3 copies - 3 average
Supreme Will
2 copies - 2 average
Dragonskull Summit
2 copies - 2 average
Search for Azcanta
2 copies - 2 average
Duress
2 copies - 2 average
Gonti, Lord of Luxury
2 copies - 2 average
Torrential Gearhulk
2 copies - 2 average
Glimmer of Genius
2 copies - 2 average
Disallow
2 copies - 2 average