If you consider these buildable stations a spoiler, then don't open any spoilers, I guess.
As far as I know, player built stations will try to get as close to these loadouts as possible, given the available blue prints.
Small LOW-TECH station (orbital station) starts with 3 modules
Small MIDLINE station (orbital station) starts with 2 modules
Small HIGH-TECH station (orbital station) starts with 3 modules, plus 2 independent, spinning shield modules (20k caps, 1k dissipation, 0,6 efficiency and fortress shield)
that you can attack, despite it being "over" the stationMedium LOW-TECH station (battle station) gets 3 more modules and some armour bits around the main (Heavy Combat) module
Medium MIDLINE station (battle station) gets 2 more modules
Medium HIGH-TECH station (battle station) gets 1 more module and a giant shield on the other side of the station
All big stations/star fortresses have a built-in minefield (low and midline ones have random ones, but high tech gets two modules that spawn mines like Doom (but better), that like to spawn 10 mines around one lasher because they don't like it). Low tech and midline star fortresses also get armour plating around all of their modules.
PD DRONES - low-tech star fortress gets 5 drones, high-tech star fortress gets 4 drones, midline star fortress gets 3 drones.
All stations have a hullmod that allows dissipation of their modules/sections to be shared between one another. All sections with fighter bays have a special hullmod that prevents replacement rate from falling down, under any condition. All high-tech stations have 2 additional shields that rotate independently from inner modules, but in synch with the sticking out citadel and heavy armour piece, which cover holes in the shields.