Most played cards in Oath:

2 Decks
Oath of Druids
8 copies - 4 average
Forbidden Orchard
8 copies - 4 average
Force of Will
8 copies - 4 average
Misty Rainforest
8 copies - 4 average
Spell Pierce
5 copies - 2.5 average
Emrakul, the Aeons Torn
4 copies - 2 average
Nature's Claim
4 copies - 2 average
Tropical Island
4 copies - 2 average
Underground Sea
4 copies - 2 average
Pithing Needle
3 copies - 1.5 average
Mental Misstep
3 copies - 1.5 average
Energy Flux
3 copies - 1.5 average
Show and Tell
3 copies - 1.5 average
Tinker
2 copies - 1 average
Leyline of the Void
2 copies - 1 average
Ancient Grudge
2 copies - 1 average
Vampiric Tutor
2 copies - 1 average
Time Walk
2 copies - 1 average
Demonic Tutor
2 copies - 1 average
Blightsteel Colossus
2 copies - 1 average