Most played cards in Dark Depths:

1 Decks
Vampire Hexmage
4 copies - 4 average
Dark Confidant
4 copies - 4 average
Mental Misstep
4 copies - 4 average
Standstill
4 copies - 4 average
Grafdigger's Cage
4 copies - 4 average
Thespian's Stage
4 copies - 4 average
Force of Will
4 copies - 4 average
Dark Depths
4 copies - 4 average
Polluted Delta
4 copies - 4 average
Mindbreak Trap
3 copies - 3 average
Underground Sea
3 copies - 3 average
Urborg, Tomb of Yawgmoth
3 copies - 3 average
Thoughtseize
2 copies - 2 average
Pithing Needle
2 copies - 2 average
Dismember
2 copies - 2 average
Flusterstorm
2 copies - 2 average
Null Rod
2 copies - 2 average
Hurkyl's Recall
2 copies - 2 average
Toxic Deluge
1 copies - 1 average
Sensei's Divining Top
1 copies - 1 average