For a long time I've wanted to make a cube for each season (spooky fall, icy winter, green spring, desert summer?).
What I have done is make "battle boxes" which are basically decks that are balanced against each other so any number of people can pick any deck and have fun. Makes teaching easy, and gives tons of replayability because of the different match-up combinations.
I like to pick a few cards that go in every deck, Bonder's Ornament is a fun one. Or proxy a black lotus for each. Makes the decks feel more like they were tailored against each other. I also make sure each deck has cards to start off the monarch and/or the initiative.
Pauper commander (PEDH) is a great format for this because the cards are super cheap so you can actually afford to make a handful of decks; and since everything is common, it makes matching power levels easier. PEDH is also fun because you can have commanders that normally wouldn't be available, letting you be more creative. Working on a self-burn voltron Raptor Hatchling deck right now.
I also have a jumpstart battle box with tons of sleeved decks. I made quite a few on my own. At this point I doubt I'll ever get to play them all. I ended up numbering the backs of the sleeves to make separating the decks easier after playing - this means you can know which deck you'll draw from next, not ideal, but never bothered me or even felt like an advantage.
I'm working on a Flesh and Blood battle box right now as well, new to that game, liking it a lot so far.
Definitely gonna make a pokemon box now, thanks for the idea. I'm thinking with all these games I might make a quick rules reference insert for each box since I always forget how to play pokemon.