And Ive already fallen in love with Kestia, the Cultivator as the head of a deck I still have built
Mill your deck while caging more cards with Mirror-Mad Phantasm, possibly leading into a Dread Return combo (Narcomoeba + Fatestitcher + Dregscape Zombie + Laboratory Maniac + Deep Analysis being one variation)
They tend to have decks and other accessories you can use to try the game too, so if you havent yet taken the plunge with the Pokmon TCG, its a great way to learn as you (and your child!) play
The most valuable are the amount of mana you have to spend, and the number of cards you have to spend that mana on
Aven Mindcensor stops your opponents, but not you, from searching your library
This ability allows you to search your deck for any Supporter card when you play Meowth from your hand to your bench