Free League has:
Mutant Year Zero (post apocalyptic sandbox, with linear adventure splats if that's your preference)
Forbiddan Lands (fantasy sandbox, with linear adventure splats if that's your preference)
Dragonbane (effectively a d20 version of forbidden lands)

Evil Hat has:
Blades in the Dark (PbtA crime/heist)
Monster of the week (PbtA scooby doo/buffy mystery solving)

Older but looks like fun:
Godbound (basically very simple d20 Exalted, for people that don't like how ridiculously complex White Wolf storyteller systems are)