The Whoniverse is a rather large place, and most of the time, the Doctor is the one in the spotlight. However, the Doctor rarely travels alone, and those trusty companions have been there to save the day, the world, and the Doctor more times than once. Some of them have become fan favorites over the years, and some were so prominent and influential to the narrative that they have more than earned their right to a spin-off of their own.
The Master
This has to be a surprising choice, considering that the Master is nearly always portrayed as an evil villain in the series who seeks to destroy the Doctor. However, while they do embody the characteristics of a classic villain, their relationship with the Doctor is multifaceted, characterized by rivalry and hostility, but also, at times, an underlying respect and even friendship.
As seen in the series, the Master is capable of great malevolence and goodness, which adds depth to the character and provides plenty of storytelling material, especially since we love anti-heroes now. Oh, and for those who might’ve missed it, the Master’s female incarnation, Missy, was the companion to Peter Capaldi’s Twelfth Doctor.
River Song
As one of the characters who can pilot the TARDIS — and she has stolen the keys from the Doctor more than once — River Song is a companion who appears the most primed for a spin-off. This is especially true if you consider just how many times the Doctor isn’t next to or inside that iconic Police Box and the fact that it is a self-thinking time machine that would very likely love a “girls trip,” it makes sense that the TARDIS could actually “serve” both River and the Doctor.
What makes River one of the prime candidates for a spin-off is the fact that she has a rather colorful history. She’s a third regeneration of Melody, a girl who was stolen as a baby from the Doctor’s companions (one of whom also made it to this list), which provides plenty of material for writers to explore. The potential for storytelling here is massive, especially since River Song is also a time traveler. Â
Martha Jones
The fandom has some really strong feelings about Martha Jones; many believe that the character had plenty of potential but was wronged by the showrunners. She was introduced during David Tennant’s tenure as the Tenth Doctor and wasn’t given the same amount of attention as other companions from that era.
Martha fell in love with the Doctor but stopped traveling with him due to unrequited love. Following her departure from the TARDIS, she married Mickey Smith, and the two became freelance alien fighters. Martha also worked with both UNIT and Torchwood, all of which could be featured in her own spin-off.
Ace
Initially a brash and reckless teenager, Ace matured into a strong and independent adult who battled some of the Doctor’s most infamous adversaries, including Daleks, the Cybermen, and the Master. She witnessed her own future fracture into different possible outcomes, one of which involved becoming a Time Lord after attending the Academy on Gallifrey.
While that version of the future resulted in her memories being wiped and Ace returning to Earth, it still would provide plenty of room for exploration of Ace’s own adventures inside the TARDIS and, quite possibly, with companions of her own.
Bill Potts
Bill Potts probably had one of the saddest companion exits in all of Who history. After being fatally shot, Bill was converted into a Cyberman, though she retained her sense of self thanks to her strong will. She was saved from her fate by Heather, a sentient alien machine-hybrid from space, who converted Bill’s essence into a sentient hybrid being like herself.
The two have then set off to explore the universe by themselves, and fans would absolutely want to see what happens to Bill Potts next, which makes her story perfect for a spin-off.
Rory Williams
Nobody really understands how Rory Willaims hasn’t received a spin-off of his own. Admittedly, he’s one of the most underrated companions in all of Who history, But, being the father of River Song, he certainly isn’t the least important.
At one point in the series, Rory dies and is resurrected as an Auton, a living-plastic duplicate with human consciousness. His version retained all his memories and emotions. After being revived, Rory spends the next 1,894 years waiting for the Pandorica to open so that he can be reunited with his love, granting him the nickname the Lone Centurion.
Now, a lot of things could have happened during those 1,894 years, and only some of the Lone Centurion’s adventures were documented. A spin-off could explore the events that have built up his legend in the Who universe, up until the moment in which he was restored to fully human, and his adventures with the Doctor and Amy.
An Honorable Mention: Sarah Jane Smith
This list wouldn’t be complete without mentioning Sarah Jane Smith, one of the Doctor’s longest-serving companions. She co-starred in 80 episodes of the show with Jon Pertwee as the Third Doctor and Tom Baker as the Fourth Doctor, but she also made several appearances in the show later on, including the New Who series. Given the character’s prominence within the Whoniverse, it’s really no wonder that she was given her own spin-off, The Sarah Jane Adventures, which ran for five seasons.
Final Thoughts
These were the few picks for hypothetical Doctor Who spin-offs the fandom would like to see. Naturally, there are countless other characters within the Whoniverse whose stories deserve further exploration, so take this list as a jumping-off point. Allow us to conclude today’s discussion by saying that one character who really deserves a spin-off of her own is definitely Jo Martin’s Fugitive Doctor. But that idea really merits its own discussion.