This all seems to be missing the point on how different modes of play work in those other games. I don't think we're comparing similar elements across different kinds of games here.
All of the Magic variants are primarily driven by restrictions on how you build a deck. Drafting is selecting from a limited, shared pool, sealed is just getting handed a restricted list of options, Commander is a highlander format with unique deckbuilding restrictions built around your chosen primary creature. There's some secondary stuff that enables a slightly different game structure, like the targeting rules in Two-Headed Giant or Commander's annoying multiple-player free for all politics, but the general shape of gameplay is the same.
West Marches is the closest to a similar sort of variant, but otherwise I'd be looking for variant kinds of character creation, or maybe subsystem variants that use existing pieces, like spell slots or skills, in different ways, instead of focusing on game length or player count.