Though the app works just fine in terms of allowing Pokmon TCG players to battle one another, its aesthetics are quite dated and certainly not befitting of a multi-billion dollar franchise
Honorable Mention #1
These Un-sets have crazy mechanics that break the Magic rules, like cards that care about the cards' art or artists, effects triggered by players saying a specific word aloud, cards costing silly amounts of mana or having fractional costs, cards that care about flavor text, etc
Secret Lair Commander: Everyone's Invited contains: - 1 foil borderless Morophon, the Boundless
18.5 Full payment for all Lots must be made to the Company by cash, electronic funds transfer or approved credit card
When Splinter Twin was still legal in Modern, decks looking to assemble the combo played four copies of each piece (and some Pestermites to boot!) just to maximize their chances of finding both together