What's your story?

A highspeed railcar, ideally big enough for freight so that you can make "walls" from various crates and scatter interesting/useful stuff around them. At some point either coming across a locked or barricaded door and having to crawl out and deal with the rushing wind and timed hazards like signs and tunnels.

The surface of a dyson sphere, preferably still under construction, so you can have a mixture of purposeful design, open areas exposed to the sun, control rooms to manage energy or maybe even move platforms around for passage.

The interior of a luxury space cruise, with the added benefit of being able to make some wild themed rooms on the justification of "it's rich people being excessive, again".

Future library, with increasingly bizarre security systems for the seemingly endless parade of even more restricted sections.

@five-by-five I'm adding your additions here because I think they are fucking awesome.

Large skyscrapers with dozens, maybe a hundred different floors

Most likely office buildings of mega-corps who can not only afford to build such buildings but also require all that space

Maybe evacuated due to a threat the party is responding to, either externally or even something caused internally, like mega-corps messing with shit they shouldn’t have

Maybe even completely abandoned due to messing with shit they shouldn’t have, and now the threat is getting ready to leave the quarantined building unless the party can stop it

A dam, churning as water passes through and filled with complex machinery to keep things working. With a variant for it being after some environmental change that drained the reservoir and now the dam is the only passage across a chasm, with the party needing to adjust the now-defunt mechanisms so they can pass through.

A hab dome in some extreme environment, an abandoned colony that only just got started. Not unlike some of the other suggestions but a bit more "open" at the costs of the risk of environmental hazards.

Adjacent to the "military tech base" thing is, of course, a spaceship. Presumably with the party launching an attack on it from a boarding vessel at some point. Mix it up by having the ship they're attacking currently docked with another ship, exchanging supplies or personnel, so now you've got two potential dungeons ships to traverse through. Maybe one is transporting cargo and has lesser security, so you board that one so you can cross over to the higher security one.

Fancy space McMansion, with a courtyard (complete with hedge maze), a fancy pool (that's also a weird underwater course or boat racing rally because this is the future wealthy), the mansion interior with Resident Evil style puzzles, and of course the bunker holding all the valuables/target for assassination/hidden intel.

Rich person's menagerie. While I'm not particularly a fan of killing a bunch of endangered space animals, you can have a bit of characterization mixed in where it's not really endangered animals but rather whatever the owner thinks is "cool" which just so happen to be encounter appropriate enemies. Rooms themed around their natural environments (rooms clearly too small and thus adding to the agitation, rooms that are big for the owner's "favorites"), corridors between exhibits with patrolling guard bots, maintenance tunnels. Lends itself to puzzle interactions (don't make eye contact with the space gorilla and you can pass through the room), and environmental interactions (guards in the way? push them into the eel pit). Can be there to rescue one of the animals, or it's a route into one of the other dungeons suggested.

When the Good Place said “Why choose to be good every day when there is no guaranteed reward now or in the afterlife… I argue that we choose to be good because of our bonds with other people and our innate desire to treat them with dignity. Simply put, we are not in this alone.” 

Dear, sweet, Littlefoot, do you remember the way to the Great Valley?  I guess so. But why do I have to know if you’re going to be with me? I’ll be with you. Even if you can’t see me. What do you mean I can’t see you? I can always see you.