Except for Mew, which is acquired through another secret mission, the other three cards can be pulled from the respective booster packs
Quick Mega Card Verification Checklist 1
(2022-09-09) In a multiplayer game, if Leyline Binding's owner leaves the game, the exiled card will return to the battlefield
The final method for collecting new cards is in the pack point exchange
For reasons likely to do with the weight of packs (the texture and extra ink of an ultra rare can make packs weigh a few micrograms more, making it easy for nefarious sorts to otherwise filter out the better packs), for a few years Pokmon card packs have come with code cards (cards that have a QR code for the online version of the game) with borders or colors indicative of the quality of the cards within
"We're seeing the people that would buy trainers and stuff, to flip for profit, now coming over to Pokmon to do the same thing." Suddenly, the reason why one person might be going into a store and buying up the entire stock started to make more sense: They're immediately in profit
