3e: Athas.org put out a lot of stuff, with some only last year. Honestly most of the adaptations of 2e settings have interesting aspects to them. 3rd party OGL settings had several hits. I kept wanting to do something with Dragonmech, whether it's a city mech or working Riftwalker into an Ultimate Magus build. The retro kitchen sink I want to run using high level low ceiling characters might involve the former, squaring off against an Athasian lifeshaper. To the extent Mutants and Masterminds can be considered closely related to 3e would allow it to fit in my best of list, as well.

d20 Modern: I want to get back on caffeine and set up a West Marches gestalt Etherscope game so badly. It would be easier if one set it on a different planet than Earth, as is so often the case.

PF1: Dreamscarred Press made a lot of useful content. City of Seven Seraphs is a fun over the top multiversal hub. Spheres ain't my bag.