I am including this photo of one of the magic related card games I have developed.
I am placing this here so you can take it and either try to figure out what it is this game is about or get inspired to create your own magic card game.
At one point I will also explain what the game is about. But until then, happy digging.

I was thinking, what if you actually buy a card game that has images and names of heroes and spells on them, but no description, and with the unfinished cards you also get 100 stickers, from which you choose which ones to stick unto your cards. This way each individual makes their own unique card game.
I like this idea of things being unfinished and developing themselves as you use them. What about houses? You buy a house that is unfinished and as you live inside it you arrive in situations when you think, "I could really use a table here." and then you have a table there. And I wouldn't even put a limit to how many times you can do this. What I would do instead, is allow the characters to keep wishing for things inside their houses and then at one point in the story show from where all of the objects are coming in fact.
Or food that alters itself as it comes in contact with your skin. The food feels what you need, 10% sour, 30% pepper, etc. and alters itself so you feel those tastes and satisfy yourself fully. But this might be a bit too fictional, so maybe find a scientific way for this to be accomplished?
What if card games were developed like this, unfinished, and they would complete themselves only when two players would sit down and engage in a battle? This way you would have an unique game each time someone would play. Could do well for a game story.