Reaper's Chronoscape series has tons of sci-fi, sci-pulp, steampunk, wildwest etc. They should be able to meet your needs for most character types with their already existing products. Soda Pop Miniatures will be producing all of their licensed Starfinder Minis and they look pretty good from the concept art we have seen. Ship minis is where i think i will have the most fun. i have a lot of ships from Firestorm Aramada that should work as well as a few odds and ends from miniature models and such. i also happen to have a lot of star wars micro machines from the current run and have no qualms about kit bashing them together to make new ships. I might pick up some of the planetfall ship minis too so i feel like i will be well prepared to run ship encounters at least.