Theme Boosters help new and casual players expand their collection with colors that they’re already invested in. Each pack contains 35 randomized cards from Zendikar Rising, built around a single color -- black, white, red, green, or blue -- or, in the case of the Party booster, the set's new Party mechanic. In nine out of 10 boosters, one card will be rare or mythic, but one booster in 10 will have two rares.