Big Finish Doctor Who audio spin-offs

In addition to the Doctor Who audio dramas featuring the Doctor, Big Finish Productions also produce audio dramas centred around other characters in the Doctor Who universe. Here is a list of the Big Finish spin-offs.
 * Bernice Summerfield - The adventures of archaeologist Bernice Summerfield, former companion of the Seventh Doctor. It was succeeded in 2014 by The New Adventures of Bernice Summerfield.
 * Charlotte Pollard - The adventures of Charlotte Pollard, former companion of the Eighth and Sixth Doctors and associate of the Viyrans.
 * The Churchill Years - Adventures of Winston Churchill and his encounters with the Doctor.
 * Counter-Measures - The Intrusion Countermeasures Group from Remembrance of the Daleks fight alien and supernatural threats in the 1960s. It was succeeded in 2016 by The New Counter-Measures.
 * Cyberman - Follows the Orion War in the 26th century, which involved the humans, androids and Cybermen.
 * Dalek Empire - Humanity fighting the Daleks across hundreds of years.
 * The Diary of River Song - The adventures of River Song when she's away from the Doctor.
 * Gallifrey - A political thriller set on Gallifrey, featuring Romana II, Leela and brand new characters such as Coordinator Narvin.
 * Graceless - Twin tracers Abby and Zara, who previously encountered the Fifth Doctor.
 * I, Davros - Davros's rise to power, from childhood to the creation of the Daleks.
 * Iris Wildthyme - Transtemporal adventurer Iris Wildthyme traverses the universe in the Celestial Omnibus.
 * Jago & Litefoot - Henry Gordon Jago and Professor George Litefoot from The Talons of Weng-Chiang investigate infernal incidents in Victorian London.
 * The Lives of Captain Jack - An audio anthology with adventures of Jack Harkness.
 * Sarah Jane Smith - Sarah Jane's adventures following the Fourth Doctor returning her to Earth and A Girl's Best Friend.
 * Torchwood - New adventures for Torchwood across history.
 * UNIT - An original UNIT team deal with threats both alien and human in the early 2000s. Following a Doctor Who special, it was succeeded in 2015 by UNIT: The New Series, featuring Kate Stewart, Osgood and a new UNIT team combating alien invasions in the 2010s.