With the caveat that I’m not keen on the terms ‘lore’ or ‘canon’ (because Doctor Who doesn’t really have either - what the show has is a constantly shifting, mutable story with ‘facts’ that are constantly contradicted),…
…What bits of ‘fan lore’ or ‘headcanon’ would you want to see made ‘real’ in the show.
For example, @Mindfog reminded me of Goronwy in Delta and the Bannermen and how I’ve always been of the opinion that he is a retired Time Lord.
Season 6b (created to explain some of the continuity niggles in The Two Doctors) is the ‘biggie’ which was, sort of, made ‘canon’ by Terrance Dicks in his novels for BBC Books.
I’ve always loved the idea that between The Awakening and Frontios, Will Chandler joined the Doctor, Tegan and Turlough for a few adventures in the TARDIS.
One that I don’t subscribe to, though, is that the War Chief was an early incarnation of the Master (something which Dicks clearly doesn’t agree with bearing in mind Timewyrm: Exodus).
What fan theories do you wish were solidified on TV? Or are there any that you think are absolute nonsense?
Don’t necessarily care if it’s like confirmed or not but one that I really love and finds holds up really well for at least NuWho is that while the Doctor can’t control his regeneration it is influenced by his subconscious (and, with no real evidence, I like to think by the TARDIS as well somehow).
A few that I really dislike:
Definitely agree about the War Chief not really making sense as an early Master. I’m also not a fan of the idea of Spy being before Missy, as I don’t think his character ignores Missy’s arc, but that he’s essentially relapsed. Also hate any theory that aims to basically just undo the Timeless Child.
Saw a detailed fanon explanation of how time works, how a TARDIS being sentient can go between different possible timelines before one is set, which a vortex manipulator for example can’t do. Also whilst a Time Lord can see the timelines and flit around them to try and get the best outcome for them, they need a non time sensitive individual to witness their actions to set in stone that timeline
My feeling was generally that the Spy Master was after Missy, but relapsed because of learning about the Timeless Child. Though another factor would just be the regeneration messing with personality, the way it always does.
Within fanon (especially in the liv/helen section of fandom) the common headcanon/fanon is sort of that Kaldor has it’s own language and that Liv Chenka doesn’t necessarily speak/write English as a first language. Which is a tiny little headcanon that I adore! A lot of Kaldoran last names read as non-English combined with Liv being mistaken for Polish a few times in canon. Carrying on from there most fic authors in that group of people tend to write it so that Liv has since learned English (re: joining the space service might have required it).
Another fun one that has come up a few times with that same group of people is that Kaldorans might age slower (evolution over time, which is plausible as they also heal faster in canon, which would also be evolution) as the planet has 18 months in a year instead of Earth’s 12 months.
It’s those two little things that are on my mind every so often and I wouldn’t mind it if they weren’t made canon, but I’d also be delighted if they were I love it conceptually when the humans that are seemingly still very human are also just that tiny bit Alien as a consequence of living on a different planet for several centuries
This reminds me of another big detailed one about how time works that i think was on r/gallifrey, basically talking about how lots of different things can be canon at once but retconned through whatever, e.g. the doctor was the other but the rammifications of the war in heaven wiped that and then he’s half human but then the time war wiped that and he’s not, etc, etc (i’m probably only half remembering it)
will see if I can find it
Edit: Can’t find it for teh life of me, if anyone else can please let me know
Well, the Doctor travels so much through time and space and meddles with things so often that the Doctor’s probably caused half their adventures to have not happened by now by changing the timeline before them…
The idea of lock states from Time 2.0, the big Time War fanfic - basically that Time Lords are much more aware of time, which also grants them awareness and small limited ability to manipulate those timelines without any use of technology. 10 uses a minor lock-state to functionally teleport behind Martha, because he chose to push together two timelines, one where he had walked behind her, and one where he hadn’t, but she could only see one of them happening. He uses it to demonstrate how humans would have had no possible way to fight in the Time War, but the narration also explains that that’s how he’s able to get lucky so often. The tiniest, tiniest massaging of the timelines. But also that it’s incredibly dangerous. I’ve also headcanoned this into a reason for Pertwee just magicking a tape reel into thin air and out of it again in Ambassadors of Death.
I’m running a very big-picture Doctor Who RPG game for my wife where she’s playing a Time Lord working for a home-brewed clandestine Time Lord organization, so I’ve tried to cram a fair bit of my own fanon into that where I can - I glommed onto the TARDIS coral deleted scene from Journey’s End. There used to be a whole planet of time-sensitive coral that original TARDISes (including the Doctor’s Type 40) were grown from, but Time Lord hubris rendered the planet uninhabitable, meaning that from that point on, there’s less and less sentient coral in the make-up of TARDISes, which is why The Doctor’s is a lot more sentient than say, modern Battle TARDISes or capsules.
That was what was indicated in the original script. For me I would have prefered them being the Doctor’s child. Having an older looking person playing someone who was actually younger than the Doctor was more interesting to me. That is my head cannon.
This is one that gains a lot of (unintentional) resonance if you put the timeless child backstory in there.
I don’t know that there’s much I want to see made canon in the show. I’m a big fan of stuff where Bad Wolf turns out to have affected Rose more deeply than indicated on the show, but a lot of it wouldn’t actually work if you tried to do it in the show. I feel like the fan lore I like tends to be like that–stuff that lets me explore alternative possibilities as opposed to stuff that works with the actual show.
That the meta-crisis Doctor is a younger version of Peter Cushing’s Doctor who ends up building a sort-of-TARDIS and going on adventures with his granddaughters, and Wilfred Mott’s maternal uncle Tom Campbell.
For all the differing answers to why the Doctor left Gallifrey, I’ve often thought the more interesting question is why he took his granddaughter with him. The Doctor was clearly discontent with life on Gallifrey but I like the idea that what pushed him to run away was seeing the same discontent in Susan, having already lived such a long first incarnation in that discontent he left wanting better for her, so she doesn’t turn out the same way.
2 of the Unbound Doctor stories explore this, effectively that he sees the corruption in the Time Lords, not just their hubris and lack of giving-a-toss about the universe, and wants to stop that happening in his favourite person on Gallifrey, Susan.
In my mind Kaldor as an human colony is mostly Slavic-originated (like how Terminus is mostly Scandinavian.) and thus Liv Chenka and Lish Toos are Slavic by descent and language. I can see the Kaldoran language as some sort of future Interslavic creole. But it also could work as a descendant from Polish. Also, it’s propably named after him: Nicholas Kaldor - Wikipedia Which means maybe there are Kaldorans out there, speaking Hungarian descended languages.
Descent wise I also think that Tasha Lem is a Williams descendant and that Madame Kovarian is Kovarian Pond. The surname Williams became Lem, and Walton became Vyon, and Vashtee surname is related to the Vashta Nerada. Though eventually I realized Kovarian surname might be related to a place named Kovar in Texas… or to Kovar the Czech surname meaning smith. As in she and Tasha appear in the smith era, so maybe Madame Kovarian was a kaldoran too!
I think that characters played by the same actor, or related actors, are also related.
I love it conceptually when the humans that are seemingly still very human are also just that tiny bit Alien as a consequence of living on a different planet for several centuries 
there are Kaldorans out there, speaking Hungarian descended languages.