My first long running campaign had all sorts of rip-offs... er..."homages".
"Star Wars" was a biggie, of course. Imperium= Evil Galactic Empire. I eventually added Jedi, who actually wound up acting more like Zhodani thought police. Kinunir-sized mini-Star Destroyers. Lightsabers!
"Dune" had monitors, ships that broke up into smaller units to land, but joined up into one big ship in space. I made a sort of mini-Death Star, of ten 5000 ton ships, each with a centerline meson gun, joining up into one long monster gun. This was after Book 4 Mercenary came out, but before Book 5 High Guard. Book 4 meson guns simply disintegrated the target in a certain radius. It was my way of getting around the 5000 ton ship maximium. Impractical, yes, but it intimidated the players :devil:. I also used the Guild Heighliners, 1000+ ton, long jump freighters that carried smaller, short jump ships in their holds.
A zooship, a modified free trader, came from a Poul Anderson story.
My version of black globe generators, mentioned in adventure 1, Kinunir, but without rules, borrowed liberally from "Mote in God's Eye".
In a later pirate based campaign, I needed a team of assasins to chase the PCs. I based them on the "Teen Titans", but explained their powers as special psionics, or cyborging.
In a weird reverse, I created a female cruiser captain who would have been a constant nemisis, had the campaign not collapsed. I even drew a sketch of her, now long lost. Years later, imagine my shock when I saw her staring at me from the cover of one of David Weber's "Honor Harrington" novels!
