Roider Union Space miners! One of the few factions that really bases themselves off of low tech doctrine, what with their modular armor. Also introduces fighter clamps, which is a more extreme version of converted fighter bays: slap fighters on anything for cheap, but have even more scuffed performance.
It also adds retrofits, which converts the dmodded civilian ships you might find in the wild to roider variants.
Legacy of Arkgneisis Adds a pirate-like faction with funky ships that get a lot of OP and nice systems to compensate for slightly inferior statlines. Don’t worry, they mostly hate the Hegemony. And only the Hegemony.
Also adds one endgame quest and some heavily d-modded wrecks. Although Derelict Contingent is busted, and Repair Docks are nice, they’re intended to be full restored.
Monkey Module is funny.
Scy Nation The lore is a multipage PDF, but to make a long story short, non-doctor scientists who just want to be left alone.
It’s really nice to use their ships in lines(especially with other tech levels!) due to thin physical profiles and high active venting. They strike hard, and then retreat to vent – if they have the support of the rest of the fleet. If they get flanked or just don’t have a line to retreat to, they’re not gonna have fun.