Sara Kingdom
Not counting her numerous appearances in Audiobooks, Sara Kingdom actually only appeared in one TV Serial, 12-part epic The Daleks’ Master Plan. Sara Kingdom was a Space Security Service agent who aided The First Doctor and Steven Taylor in the defeat of the Daleks and the egocentric megalomaniac, Mavic Chen. Alas, she lost her own life in the process.
Podcast
C021 The Daleks’ Master Plan
The Doctor robs the Daleks, gains two companions, loses three, and then we even get an appearance by the monk. Epic!