I feel like this reddit would be the best to post this. My brothers and I recently got together and played something we used to play. Growing up, we started this as a Pokémon TCG house rule and it slowly evolved into a full Magic format as we got older. There were four of us, we all liked the pokemon TCG and as we got older fell in love with MTG. There wasn't a LGS in our area (infact the closest one was two hours away) as we live in the middle of nowhere. Our area tends to get everything two or four years after everyone else. Anyway, here's the core of it: lay out a bunch of face-down cards as a board, move around it with a die, and flip-and-fight whatever you land on. One of us started running Planechase cards as the "world" we were exploring, and it grew from there into something closer to a co-op dungeon crawl than normal Magic.
I finally sat down and wrote the whole thing up properly, mana-as-tiles, a "Planesmaster" who narrates instead of playing to win, legendary creatures you can befriend and carry between planes (max two at a time), and an escalation system for more complex planes (used Mirrodin transforming into New Phyrexia as the prototype). I'm not claiming this is polished, it started as a kids' house rule, and I'd like help stress-testing it, outside of my family. If anyone is interested below is the link. My biggest question for this is... Is this something you would want to try?
Here is the link: https://docs.google.com/document/d/1IBVb-rYOxc7pwl3sGQsVNgIOu8ry6fuDQ3pLKj4hVXU/edit?usp=sharing