In your deck, you should have three different types of cards: Pokemon - The most important cards are the actual Pokemon cards, of which there're multiple per individual pocket monster, since each Pokemon usually has several evolutions
It used to be that if you cast a cascade card, such as Shardless Agent, that you could then cast either side of a card like this
Often played by commanders like Zinnia Valley's Voice, Baylen the Haymaker, Ms Bumbleflower, Jetmir Nexus of Revels, Derevi Empyrial Tactician
They exist at a rarity more common than common
Theres also a lot of gorgeous Mega Evolution art to grab off of their trading cards in this set, but we all know the Trading Card Game will always boil down to if theres a rare Charizard, and therefore this must be near the top of the list
The cards are highly sought after by collectors due to their rarity and aesthetic appeal, as well as their connection to two popular and powerful Pokemon