Most played cards in Death and Taxes:

4 Decks
Ghost Quarter
16 copies - 4 average
Thalia, Guardian of Thraben
16 copies - 4 average
Leonin Arbiter
16 copies - 4 average
Flickerwisp
16 copies - 4 average
Path to Exile
16 copies - 4 average
Aether Vial
16 copies - 4 average
Blade Splicer
12 copies - 3 average
Thraben Inspector
12 copies - 3 average
Restoration Angel
12 copies - 3 average
Relic of Progenitus
11 copies - 2.75 average
Tectonic Edge
11 copies - 2.75 average
Stony Silence
9 copies - 2.25 average
Mirran Crusader
8 copies - 2 average
Horizon Canopy
8 copies - 2 average
Burrenton Forge-Tender
6 copies - 1.5 average
Sunlance
6 copies - 1.5 average
Serra Avenger
5 copies - 1.25 average
Grafdigger's Cage
5 copies - 1.25 average
Eldrazi Temple
4 copies - 1 average
Tidehollow Sculler
4 copies - 1 average