Most played cards in Mardu Rack:

1 Decks
Badlands
4 copies - 4 average
Mishra's Factory
4 copies - 4 average
Lightning Bolt
4 copies - 4 average
The Rack
4 copies - 4 average
Red Elemental Blast
4 copies - 4 average
Disenchant
4 copies - 4 average
Hypnotic Specter
4 copies - 4 average
Order of the Ebon Hand
4 copies - 4 average
Dark Ritual
4 copies - 4 average
Chain Lightning
4 copies - 4 average
City of Brass
4 copies - 4 average
Hymn to Tourach
4 copies - 4 average
Scrubland
3 copies - 3 average
Sedge Troll
2 copies - 2 average
Terror
2 copies - 2 average
Swords to Plowshares
2 copies - 2 average
Sengir Vampire
2 copies - 2 average
Earthquake
1 copies - 1 average
Fireball
1 copies - 1 average
Balance
1 copies - 1 average