Activated mana abilities may be played both when a player has priority and in process of casting a spell, activating an ability, resolving a spell or ability, if any such action requires a mana payment
That's where it's at
There are fifteen different cards to collect: Bewear, Chinchou, Cutiefly, Drampa, Flaaffy, Gossifleur, Growlithe, Lapras, Ledyba, Pangoro, Pikachu, Rowlet, Smeargle, Tynamo, and Victini
Definitely powerful, but needs a bit of work to get there
Any ante cards from game losses are exiled for the rest of the match
What custom Magic cards usually means (so you dont overcomplicate it) Most people making custom Magic: The Gathering cards fall into one of these buckets: Alt-art re-skins: Same card text, different art and vibe (your Sol Ring is now a cursed waffle iron, as it should be)