Fraction

The Fraction appeared to be a group of Time Lords which wandered the universe and held great power. They were annihilated by Tannis, with only the Minister of Chance surviving, his powers removed by the Doctor. The Fraction was succeeded by Ace. (WC: [[Death Comes to Time)

Behind the scenes
The canonicity of Death Comes to Time is unclear.

In Death Comes to Time, the Time Lords appear to be very different from their usual portrayal. They seem to be mystical wanderers rather than stagnant bureaucrats. Tannis apparently refers to these Time Lords as "the Fraction". Since the destruction of the Fraction in Death Comes to Time seemed to be treated as the extinction of the Time Lords, the status of the other Time Lords in that story is unclear.