Charizard ex, when fully built, is currently the only Pokemon capable of knocking out other Pokemon ex with a single attack, making the deck a rather formidable one to go against unless you can put a stop to them early on
Each round, every player plays a card
They are perhaps the most important tool for being reliably unfair, but there are several tutor variants in the Cube with various restrictions and drawbacks
Although it only has 90 health, it has some incredible abilities that can turn it into a tank
Although often thought of as a "restart the game" effect, it doesn't exactly function that way as even though you do start a new game, you will eventually return to the original game in the exact state that it was in when the card was played
While that is probably not going to happen often, and you might have other targets for those counters, it shouldnt be overlooked that this on an empty board, maybe after a board wipe, will be dangerous