Switched up the question a bit, so I could answer "Probably PBTA stuff. Probably."
For me it's a VERY GOOD mix of the kind of game approach that favors the GMing style I developed primarily with Amber DRPG, but built on a system and mechanics that regularly inject unexpected elements into the game, which was one of the things lying at the heart of my problem(s) with Amber. (And, more recently, Fate.)
Easiest would be something super-simple like World of Dungeons or Risus or FAE.
And to be fair, I'm comfortable and enjoy running pretty much anything at the table. But something like DnD or DCC requires a degree of nuts and bolts prep that I either don't have bandwidth for [^1], or don't enjoy (CR-balanced DnD encounters, frex) – with those sorts of games, I''m going to run a module or something, so I don't have to do that prep, and in those cases I don't end up bringing as much of my own stuff to the game.
So. PbtA. That's my sweet spot when it comes to all aspects of GMing.
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[^1]: The joke about not having enough bandwidth to do prep is, of course, that I did literally hours and hours of prep for only the first session of our Masks game. World maps. NPCs. Encounters… At least an hour just watching awkward celebrity interviews, to get ideas.
So I guess it's more "I don't have time for prep I don't really, really enjoy."