Menti Celesti
The Menti Celesti were a group of deities which the ancient Gallifreyans worshipped during the Pythia's rule. They were made up of the leading Eternals, including Pain, Time, Death, (PROSE: Cat's Cradle: Time's Crucible) Life, and Fate. (PROSE: Hark! The Herald Angels Sing)
Death once explained to Timothy Dean that she and her many sisters were the dreams of Time Lords, leaking across the universe and occasionally given form by beings such as the Timewyrm. She also mentioned that they appeared to some Time Lords in nightmares or near-death experiences and made deals, sometimes even making the Time Lord their Champion. (PROSE: Human Nature)
The hermit K'anpo Rimpoche once told the First Doctor to fast for three days and three nights to make supplications to the Menti Celesti. (PROSE: Timewyrm: Revelation)
Prior to the War in Heaven, all the goddesses save Death fled the Spiral Politic in their six-folded home. (PROSE: Hark! The Herald Angels Sing)
Behind the scenes
Mags L. Halliday's A Handful of Silver from the 1999 charity anthology Perfect Timing 2 asserts there is another Gallifreyan Goddess named Fate. Chris McKeon's unlicensed 2008 completion of Craig Hinton's Time's Champion introduced Life and Hope. Life and Fate later appeared in Jacob Black's Hark! The Herald Angels Sing, from the Faction Paradox series.
The Menti Celesti bear strong similarities to the Endless from Neil Gaiman's DC comic, The Sandman. The eponymous Dream is a being based on the dreams of mortals, and likewise Death is a prominent member.