An updated answer is that while Jenny has not reappeared on television (as of November 2023), she has appeared in other media, including short stories and especially comics and audio adventures. These two major storylines may not be compatible from a continuity standpoint, mostly because of interactions she has with the Doctor; certainly the audio adventures are generally more consistent with later TV stories where the Doctor seems to still think she is dead, since their audio encounters are often forgotten or rewritten thanks to weird time travel effects.
Comic book adventures
Jenny first reappeared in several of Titan Comics’ ongoing Doctor Who titles, beginning with the 50th anniversary story “Prisoners of Time”, where she meets many of the Doctor’s companions.
After this she acquires a Gallifreyan “bow ship” from the time of their war with the ancient vampires and fashions herself armour featuring the Seal of Rassilon. She has a brief encounter with the Fifth Doctor, then fails to catch up with him across multiple incarnations. She loses the bow ship when she helps several Doctors save the universe from a white hole, but is afterwards returned to her future time by the Doctor. (Most of this happens in the crossover event “The Lost Dimension” appearing across the various Doctors’ individual comic book lines.)
Big Finish gave Jenny, still played by Georgia Tennant (neé Moffet), her own mini-series in 2018, with a follow-up in 2021. She’s also appeared in several other Big Finish audio plays, including twice appearing alongside Georgia’s real life father Peter Davison as the Doctor.
In the audio series she has her own adventures in various stolen or borrowed spaceships, including picking up a mysterious companion named Noah, and fleeing from a cyborg bounty hunter named COLT-5000, who wants the valuable Time Lord biodata contained in her DNA.
Jenny does time travel on a few occasions, and in her most recently published adventure (as part of the sixtieth anniversary series Once and Future) ended up in the extremely far future, though it’s uncertain at what point in her adventures this occurs. But assuming that’s her current whereabouts, she has means to escape and is likely still out there having adventures.