Team-up co-op for other sets

I was thinking of turning some set like Bloomburrow or Avatar into a co-op like TMNT. The kids are small and would care for TMNT as much as I do (kek)... But an in-universe or a fantasy-based universe set (BLB or TLA) would probably be more interesting for everyone, so I was wondering if anyone had already thought about it, or if there are other co-op modes that exist etc.

Rambling/brainstorming..: Top of my head I remember reading somewhere about a way to play test your decks against a monogreen random deck of only lands and creatures, where you reveal creatures cards until you hit a land for X turns then attack. Something in this category (quite similar to team-up)

For TLA's theme I was thinking of "copying" the TMNT boss and event cards changing the wordings of "foot disciple" and whatnot with "Soldier" and have bosses like Azula, Ozai or whatever. Making some mono decks mainly based on the Jumpstart decks.

Any pointers?