Most played cards in Power Monolith:

2 Decks
Basalt Monolith
8 copies - 4 average
Power Artifact
8 copies - 4 average
City of Brass
7 copies - 3.5 average
Transmute Artifact
7 copies - 3.5 average
Volcanic Island
7 copies - 3.5 average
Power Sink
7 copies - 3.5 average
Fireball
6 copies - 3 average
Red Elemental Blast
6 copies - 3 average
Icy Manipulator
5 copies - 2.5 average
Shivan Dragon
4 copies - 2 average
Serendib Efreet
4 copies - 2 average
Fellwar Stone
4 copies - 2 average
Blood Moon
4 copies - 2 average
Underground Sea
3 copies - 1.5 average
Jayemdae Tome
3 copies - 1.5 average
Guardian Beast
3 copies - 1.5 average
Timetwister
2 copies - 1 average
Time Walk
2 copies - 1 average
Ancestral Recall
2 copies - 1 average
Strip Mine
2 copies - 1 average