Rocketship Games has a small selection of STL files for Sci-Fi games.
Thunder Chrome - Sci-Fi Printable Scenery
Kickstarters: Black Hallows: Townsfolk 1 & 2
Precinct 187
3D Gaming Accessories
https://www.kickstarter.com/projects/292543184/nine-worlds
https://www.kickstarter.com/projects/292543184/meepleverse-2-a-meeple-odyssey
https://www.kickstarter.com/projects/292543184/starfolke?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/meepleverse?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/beyond-the-copper-doors?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/urzan-liberty-corps?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/townsfolke-2-the-free-folke?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/kingdoms-of-hell?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/wallhalla-modular-miniature-display-shelves?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/kyn-finvara-3d-printable-goblin-village?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/townsfolke?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/scatterblocks?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/teledrome?ref=makerfun3d.com
https://www.kickstarter.com/projects/292543184/zod-3d-printable-terrain-tiles?ref=makerfun3d.com
https://www.kickstarter.com/projects/haylandgames/mega-city-vehicles-3d-printable-files/posts
https://www.kickstarter.com/projects/haylandgames/scatter-pucks-paint-holder