The Preserves feature in Star Trek Online. They are the sane people as the ancient humanoids from TNG: The Chase.
STO posits that their civilisation is long gone but there a lot of hibernating survivors, awakening now and then to explore the universe (most recently in 2409, when the Breen hoped to find an ancient weapon cache; now under the protection of the Deferi) and see what their descendant species have achieved.
Hmm... I'm usually quite vehemently opposed to the idea that the Preservers (a race or organization whose one known action occurred no earlier than the 17th century and is thus contemporary with ourselves rather than ancient) have anything to do with the Progenitors from "The Chase," who lived unimaginably farther back in time and had completely different methods from the Preservers (they didn't preserve existing species, they triggered the evolution of new ones billions of years down the road). But this explanation, while still a profound case of Small Universe Syndrome, at least acknowledges the immense gulf in time we're dealing with. And the hibernation idea reminds me a bit of what I did with the Manraloth in The Buried Age
, though it would be presumptuous of me to assume any actual homage was involved.