You may be looking for the ancient humanoids, or the Stargazer novel Progenitor.

The Aldean Progenitors built the Custodian, an interactive computer, on the planet Aldea hundreds of centuries ago.

They prepared the planet with everything that the small colony of Aldeans would ever need. They also supplied a massive power supply, a defensive shield, a repulsor beam and a planet-wide cloaking device.

In 2364, with the intervention of the crew of the USS Enterprise-D, the Aldeans re-discovered how the Custodian worked, and began to relearn all their skills. (TNG: "When The Bough Breaks")

It is unknown who the Aldean progenitors were, but it is likely that they were an advanced race, who prepared the planet for the Aldean settlers, in a similar way that the Caretaker provided for the Ocampa.