Most played cards in Mono-Blue Prison:

2 Decks
Jace's Sanctum
8 copies - 4 average
Prism Ring
8 copies - 4 average
Engulf the Shore
8 copies - 4 average
Anticipate
8 copies - 4 average
Part the Waterveil
8 copies - 4 average
Pore Over the Pages
7 copies - 3.5 average
Thing in the Ice
7 copies - 3.5 average
Hydrolash
7 copies - 3.5 average
Day's Undoing
6 copies - 3 average
Take Inventory
4 copies - 2 average
Sunken Hollow
4 copies - 2 average
Prairie Stream
4 copies - 2 average
Negate
4 copies - 2 average
Nagging Thoughts
4 copies - 2 average
Displacement Wave
2 copies - 1 average
Dragonlord Silumgar
2 copies - 1 average
Unsubstantiate
2 copies - 1 average
Summary Dismissal
2 copies - 1 average
Noyan Dar, Roil Shaper
2 copies - 1 average
Rise from the Tides
2 copies - 1 average