This is a cube meant to be drafted like a standard Magic set with 1 rare/ mythic, 3 uncommon, and 11 commons. However, the cube doesn't just contain cards from one set, instead, it includes cards from across Magic's history like a usual cube. There are archetypes centered around the shard 3 color combinations.
ARCHETYPES
It should contain 101 commons, 80 uncommons, 53 rares, 15 mythic rares. However, in drafting, there are 3 of each common, 2 of each uncommon, and 1 of each rare and mythic.