Most played cards in Eldrazi and Taxes:

63 Decks
Chalice of the Void
251 copies - 3.98 average
Ancient Tomb
251 copies - 3.98 average
Thought-Knot Seer
242 copies - 3.84 average
Cavern of Souls
237 copies - 3.76 average
Eldrazi Displacer
237 copies - 3.76 average
Thalia, Guardian of Thraben
235 copies - 3.73 average
Wasteland
229 copies - 3.63 average
Eldrazi Temple
224 copies - 3.56 average
Reality Smasher
213 copies - 3.38 average
Mox Diamond
164 copies - 2.6 average
Karakas
154 copies - 2.44 average
Thalia, Heretic Cathar
149 copies - 2.37 average
Containment Priest
145 copies - 2.3 average
Swords to Plowshares
123 copies - 1.95 average
Rest in Peace
94 copies - 1.49 average
Disenchant
94 copies - 1.49 average
Walking Ballista
90 copies - 1.43 average
Palace Jailer
88 copies - 1.4 average
Thorn of Amethyst
81 copies - 1.29 average
Leyline of the Void
72 copies - 1.14 average