all mtg cards with partner The Best In Commander 2016 Mechanics | MAGIC:

Best of all because Draft and Sealed (the most common prerelease formats) only use cards people open in packs at the event you dont have to come with a deck, or worry about some decades-long MTG veteran walking in with a super powerful deck

A card might read When this creature enters the battlefield, if you control another creature, draw a card

Your life total is padded whenever a creature dies, meaning you'll have more than enough time to activate your Crystal, even if you're being targeted by your opponents

That means these six slots in the Set Booster will range from five commons and one uncommon to zero commons and six uncommons