Four Knocks, basically a white Phyrexian Arena with an expiration date
A Flash counter and or blocker, there's some very fun way to use this, especially during things where your opponent may assume they're safe to be greedy, such as on a turn-ending before untapping fully, and I agree with Loxi: players like to tap out a lot carelessly
Active Player priority Each turn, the Active Player priority is passed to the player whose turn it is
These cards are not legal without prior agreement from the other players in the game, and may steer your playgroup to avoid other, similar cards
Yes, blister packs can contain exclusive promo cards that are not found in regular booster packs, making them a unique addition to your collection