Zodin (the Terrible)
The Doctor encountered (and reminisced about) the Terrible Zodin on a number of untelevised occasions. He first met her some time prior to his second incarnation. Iris Wildthyme also claimed to have met her.
Zodin was involved in an adventure which caused the Doctor to interact with multiple incarnations of himself. Following this she erased their memories of the incident using "mind rubbers", preventing the later Doctors involved from remembering having experienced the events before Cold Fusion.
This did not prevent the Doctor from remembering enough of the adventure to frequently bore people to sleep with a long-winded account of it, although he was incapable of consistently recalling whether she was assisted in her schemes by mutant kangaroos or by giant grasshoppers (Legacy).
Jamie (The Colony of Lies) and Mel (Millennial Rites) both experienced the incident. The Brigadier was not involved. (The Doctor implied that their first meeting might happen in the Brigadier's personal future.) (The Five Doctors), however may have assisted Iris Wildthyme against Zodin in a separate adventure on the planet Mars.