Counterspell It's hard to find a bluer card than Counterspell: It's been around since Day 1, and it's still very relevant without being overpowered
Sporting a standard 5000 power and 5 Life, Buggy's entire mechanical identity focuses on bypassing the traditional resource curve to swarm the board with heavyweight threats well ahead of schedule
Sire of Seven Deaths Sire of Seven Deaths has seven abilities and they add up to one monster that is really difficult to deal with
Playing a council's dilemma card opens up a whole Magic mini-game of voting, letting you play cards like Brago's RepresentativeBrago's Representative and Illusion of ChoiceIllusion of Choice that just don't do anything in a normal deck
It also targets and destroys 1 card if a "Tearlaments" monster is returned from the field/GY to the Deck/Extra Deck, providing additional advantage from "Tearlaments" Fusion Summons, even in the opponent's turn
Armored Mewtwo Armored Mewtwo is probably the first Pokmon that comes to mind when you say 'rare Pokmon in Pokmon Go'