We saw the Lakul
in ST:GEN in a purplish scheme, and she probably was a Federation ship as per various cues (Whorfin
class, sister ship to Robert Fox
, NFT registry prefix, hauling people to Earth).
We also saw (parts of) the Santa Maria
in DS9 "Paradise" in a very Starfleet-like white-with-red-cheat-lines livery. Her registry isn't of the N series, but BTR (a Blues Brothers in-joke), but as with the Robert Fox
, both her name and her class name (Erewhon
) are obviously human in origin. Unless it's a huge coincidence and some alien culture actually uses a name that is Nowhere misspelled backwards like Samuel Butler did it...
Then there's the Rigelian transport in DS9 "Vortex" that is a reuse of the Pakled miniature, in series of browns, reds and greens. At least some Rigelians are supposedly UFP members.
And then there are the old Vulcan ships of TNG "Unification", in bluish colors, but after a brief stint as the Tosk vessel the model is reused in DS9 "For the Cause", again supposedly operated by Vulcans but now colored brown.
That about wraps it up as far as onscreen UFP civilian ships in the TNG era are concerned. Of course, ST:TMP has the pink Vulcan shuttle that looks grey on screen...