pokemon mega japanese booster box Dream EX – Keef's Cards and the chance to pull rare and exclusive cards — including what’s already looking like one of the most popular cards of the 21st century Amazon.com: Pokemon Card Game Mega

The other way you want to look at your ultimate is in contrast to the other things your planeswalker does

your opponent takes no battle damage from attacks involving that face-up monster until the end of this turn, also its ATK becomes (permanently) the combined original ATK of all "Meklord" monsters you currently control

Unseen Forces may have some spotty history with its Gold Stars, but imo has the best lineup of ex cards in the era (TRR could also be argued)

Pikachu on the Ball The Pikachu on the Ball card, like most others on this list was a special promotional Pikachu card

Canyon Jerboa is from Zendikar Rising , but there's no reason a similar creature can't appear across the multiverse in the Bloomburrow set