If an opponent tries to use any effect that would add a card from their Deck to their hand, Special Summon a monster from their Deck, or send a card from their Deck to their Graveyard, players can discard this card from their hand to negate the effect
Seeing new cards is fun, but that's true of any booster with new cards
If more quantity or very special crafts, the lead time needs to be discussed
Many excellent combat tricks, equipment, and creatures are able to give double strike to others, but I wont include them here to keep things simple
Mew EX and Mew VMAX cards represent some of the most powerful and valuable variants available
In order to express this mechanically, many of the Jeskai-aligned cards in this release have abilities that care about the second spell you cast in a turn