Last of the Time Lords

You may be looking for the TV story of the same name.

In several of their incarnations, the Doctor considered themselves to be "the Last of the Time Lords". (TV: Gridlock)

By reading Adam Mitchell's mind via his infospike, the Jagrafess and the Editor learnt that the Ninth Doctor was the last of the Time Lords. (TV: The Long Game)

The Family of Blood knew the Tenth Doctor to be the last of the Time Lords, who they understood to be a "wise and ancient race". (TV: Human Nature)

General Staal of the Tenth Sontaran Battle Fleet knew the Doctor to be the last of the Time Lords, and savoured the prospect of him dying in the Sontaran invasion of Earth. (TV: The Sontaran Stratagem)

After discovering that the War Master had survived the Last Great Time War, the Doctor rejoiced in the knowledge that he "might not be the last one", despite the threat the other Time Lord presented; (TV: Utopia) even after the Eleventh Doctor teamed up with several of his past and future regenerations to preserve Gallifrey in a pocket universe, (TV: The Day of the Doctor) with the Time Lords managing to return to the universe, albeit hiding in fear at the end of the time continuum with nothing anywhere near their old power, (TV: Hell Bent) the Twelfth Doctor continued to hold himself and Missy to be the "Last of the Time Lords", introducing Missy to Bill Potts as "the other Last of the Time Lords". (TV: The Pilot)

Clara Oswald applied the title "Last of the Time Lords" to the Doctor as equivalent to Robin Hood, the "Prince of Thieves". (TV: Robot of Sherwood)