Most played cards in Show and Tell:

4 Decks
Force of Will
16 copies - 4 average
Ponder
16 copies - 4 average
Lotus Petal
16 copies - 4 average
Brainstorm
16 copies - 4 average
Show and Tell
16 copies - 4 average
Ancient Tomb
12 copies - 3 average
Sneak Attack
11 copies - 2.75 average
Emrakul, the Aeons Torn
11 copies - 2.75 average
Scalding Tarn
10 copies - 2.5 average
Griselbrand
10 copies - 2.5 average
Volcanic Island
9 copies - 2.25 average
Flooded Strand
8 copies - 2 average
Stifle
8 copies - 2 average
Omniscience
8 copies - 2 average
Flusterstorm
7 copies - 1.75 average
Atraxa, Grand Unifier
6 copies - 1.5 average
Misty Rainforest
6 copies - 1.5 average
Daze
5 copies - 1.25 average
Impulse
4 copies - 1 average
Defense Grid
4 copies - 1 average