japanese booster box pokemon Mask of Change with at least one guaranteed Pokémon ex or Mega Evolution ex per pack Japanese Pokemon Mega Brave Booster

First, you have Radiant Greninja

C Common Tearlaments Cryme X TRAP Counter When a Spell/Trap Card, or monster effect, is activated, while you control a "Tearlaments" monster or "Visas Starfrost": Negate the activation, and if you do, shuffle that card into the Deck, then send 1 monster from your hand to the GY

You can also look for selections that have multiple high-rarity cards since the price only goes as high as the best rarity

Ugin is at least the most deflating card of the year, coming down to sweep away all the work you did building a board earlier in the game and likely leaving behind a massive high-loyalty planeswalker to boot