Amy, portrayed by Ciara Janson, is a companion of the Fifth Doctor in the Key 2 Time series, which includes the plays The Judgement of Isskar, The Destroyer of Delights and The Chaos Pool.
Antimony was a companion of the Seventh Doctor and appeared in the webcast story Death Comes to Time by Colin Meek (widely understood to be a pseudonym for Dan Freedman).
Thomas Brewster, portrayed by John Pickard, was the travelling companion of the Fifth Doctor and Nyssa during a limited story arc in the Big Finish Productions audio dramas.
Alison Cheney was a companion of the Doctor who appeared in the flash-animated serial Scream of the Shalka by Paul Cornell and the short story The Feast of the Stone by Cavan Scott and Mark Wright.
After the Doctor's investigations saw him working with German and British intelligence to thwart an attempted takeover of Earth by a race of sentient waveforms, he invited Constance to travel with him as a temporary reprieve from her duties.
After meeting Rassilon and the High Council on Gallifrey, Cinder was kidnapped by the Time Lords Karlax and The Castellan, and subjected to a mind probe to verify The Doctor's story.
The Doctor rescued her from them and they fled to the Death Zone on Gallifrey, and took Borusa, who was being used by Rassilon as a possibility engine, from his captivity in the Dark Tower at its center.
The name Claudia is an in-joke on Parkin's part, referring to The Stranger by Portia Da Costa (Wendy Wootton), an erotic novel in Virgin Publishing's Black Lace range.
It is eventually revealed that she is a living painting brought to life, bought by the Twelfth Doctor in an auction, who made arrangements that she would travel with his eighth incarnation.
A companion of the Third Doctor, introduced in the Radio 5 audio drama The Paradise of Death and played by Richard Pearce, Jeremy is an inexperienced photographer for Metropolitan, the magazine Sarah Jane Smith works for, with the character mainly being used to provide comic relief.
At the end of the novel, following his death, it is revealed he was Jeremy, whose mental problems began when he carelessly activated the Doctor's Image Reproduction Integrating System while the rest of UNIT were too distracted by the current crisis to stop him sitting in it (Planet of the Spiders).
Accepting his offer to be taken off the island, they first travel back to the Doctor's universe where they thwart a plan by the Meddling Monk and the Ice Warriors to create a gigantic sonic cannon.
This process entails changing the young William's timeline so that he never joined the sixth Doctor on his fishing trip, but instead developed his musical talent without the influence of the vortex.
Philippa (Flip) Jackson (later Ramon) is a young woman who, with her boyfriend Jared, is transported from modern day London to a sentient planet called Symbios on a tube train which passes through a temporal breach.
Flip returns in the January 2012 release, The Curse of Davros where, journeying home on a night bus, she and Jared witness the crash of a Dalek Scout Ship.
Angela Jennings is briefly a companion of the Sixth Doctor, who met her on the planet Torrok in 2191 in the Virgin Missing Adventures novel Time of Your Life by Steve Lyons.
No mention is ever made of their parents and in their final adventure, by which time they are teenagers, the Doctor enrols them in the Galactic University on the planet Zebadee rather than returning them to 20th Century Earth.
Eventually, with the help of Rassilon, Merlin, and the Matrix-powered Time Lord agent known as Shayde, the Doctor confronts Melanicus in a time-altered version of a Stockbridge church.
A short story, "Birth of a Renegade" by Eric Saward published in the Radio Times special commemorating the 20th anniversary of Doctor Who, had previously established Lady Larna as the true Gallifreyan name of Susan Foreman.
A companion of the Eighth Doctor first mentioned in a flashback sequence in the novel The Year of Intelligent Tigers by Kate Orman, which took place in the South Seas in 1935.
When the Sarah Jane audios were initially announced, the role of Ellie Martin was listed as (books companion) Sam Jones; her "eco-warrior" past may be a reference to that former origin.
This Doctor (played by David Collings) had raised Ruth since 2039, when her father, Dr Vollmer, was lost in the destruction of the Deep-sea Energy Exploration Project (DEEP) undersea naval base.
A companion of the Eighth Doctor mentioned in The Gallifrey Chronicles by Lance Parkin and possibly taken from the Telos novella Rip Tide by Louise Cooper.
Molly O'Sullivan (played by Ruth Bradley) is an Irish Voluntary Aid Detachment nursing assistant in World War I and companion of the Eighth Doctor.
She first met the Doctor and Frobisher on A-Lux in the story A Cold Day in Hell (DWM#130-#133), written by Simon Furman and drawn by John Ridgway.
In the very next story, Redemption (DWM #134), Olla's former master, the Vachysian warlord Skaroux (a legal enforcer for the Galactic Federation), intercepted the TARDIS and demanded her return.
Majenta Pryce is introduced in the Doctor Who Magazine issue 394 comic strip "Hotel Historia" as an alien entrepreneur running an illegal time-travel operation on Earth.
She is now a convict on a space-station prison where the inmates are subject to repeated memory wipes, supposedly to rehabilitate them but actually to feed parasitic lifeforms called the Memovax.
Once back on Gallifrey, the Doctor refuses to go on any more missions for the Agency unless various conditions are met, including the placing of Serena's name on the Gallifreyan Honour Roll, and that he be allowed to tell her family how she died.
Mathew Sharpe (George Shear) is a space pilot from the far future who the Sixth Doctor is seen travelling with in the Big Finish story The Lure of the Nomad.