Considering I'm a small 3PP for Starfinder, I only use my 'other' setting, and have never used, nor would use the Pact Worlds - this is not a criticism for the Pact Worlds, rather setting design has always been a major driver of the games I run, so I never use the default setting. I didn't use Golarian in my Pathfinder Games, nor Forgotten Realms (or Greyhawk) in my D&D games - I always homebrew. Plus unless I'm publishing community content (for no profit) I cannot use the Pact Worlds as third party.
I've been working on a setting of many colonies in deeper space, away from the Core worlds the humans originated (Earth) and surrounding worlds. There's an animosity between the colonies and the old Core worlds. I call it the Confederation of Independent Colonies of Colonial Space. (The Core worlds are in Corporate Space, the next beyond reaches are Colonial Space).
I got sidetracked creating a ship supplement for Spelljammer, but releases are coming out, and I'm ready to go back to my Starfinder development. I had plans to create a general guide to Colonial Space, then a series of mini-guides one star system/colony at a time with local ships, equipment, factions, map locations, events within each. Below is the draft series of cover designs I have plans for books in this series.
Last year I published
The Planet Builder a set of tables and rules for generating scientifically viable entire star systems (co-written by an astrophysicist), a star system stat block, and a Planet Point system allowing you to adjust your system to better meet your liking (you can move planets to different orbits by spending points), and you can add technology and resource stations to process the resources in your system so it can grow over time. The stat blocks for all the Colony mini guides are generated from the Planet Builder.