General things I love: Girls being awesome! Fairytale fusions! AUs (seriously, any of these characters, throw them into another universe and I will be beside myself with excitement)! Steampunk and all the charmingly ridiculous trappings that go with it! Happy endings, fluff that makes me cry, magic being an everyday thing, moral ambiguity, adventures and action and love not always being straightforward (but sometimes it is, and that's wonderful too).
I'd really prefer not to read non-con, non-canon character death, racism, homophobia or ableism, and I'd rather see characters interacting and having adventures and experiencing the world rather than something angsty and introspective, but it doesn't have to pure sunshine all the time. Creepy, atmospheric horror makes me clap my hands with glee just as much as ridic crack fic does, so please go with whatever inspires you!
Mary Poppins (1964)
If you're unfamiliar with the fandom but curious: IMDB link, & the whole film is on youtube :D
Mary Poppins is a Time Lord.
Or, if you're not familiar with Doctor Who/don't want to write that - anything about her life pre- or post-film, previous families she's worked for or visiting Jane and Michael when they're older, or maybe even what retirement for Mary Poppins would actually entail. Anything focused on her would be brilliant!
I really, really love her dimensions-defying bag and the way she views strange, brilliant things as entirely normal and her talking umbrella and her love of humanity and how fiendishly clever she is and especially "I never explain anything." Even if you don't want to go the Doctor Who crossover route, just seeing more of Mary would delight me! Seeing her with another family, or where the wind takes her between jobs.
If you want to write about her adventures as a Time Lord - again, anything, although I would prefer it if the focus was entirely on Mary and her life, rather than any overlap with the Doctor's (then again, the idea of them meeting up and having tea and discussing why they can't stay away from these humans is also wonderful, and I kind of adore the idea of her being Twelve). I'd love to see her time at the Academy or how she came to Earth and just how long she's been here (the legend of Mary Poppins throughout the ages could be fascinating!). Basically I'm just going to flail my hands and make happy noises about anything that involves Mary Poppins being from Gallifrey.
Bunny and the Bull
Stephen | Bunny
If you're unfamiliar with the fandom but curious: IMDB link, trailer, and it is available online :D
I would love to see Stephen/Bunny is some form, even if it's entirely in Stephen's head - but if you prefer gen fic (which is fine!) then any sort of surreal adventure with them, because that's why I'm so madly in love with this film. Seeing any of the other characters again would be a delight (I adored Eloisa, but optional detail is very much optional), and anything exploring their friendship/how they met/other times Bunny has drawn Stephen into something against his will.
I love the imagery, the patchwork, paper-cutout-world and the fascinatingly weird characters and the humour and the underlying darkness. Something in the style of the film, with Stephen remembering another adventure with Bunny while he's still in the house, or what happens on Stephen's trip back to Spain, or anything involving Eloisa, her life and backstory and Conchetta, would be wonderful! I would love to see more of her.
Antimony Carver | Katerina Donlan
If you're unfamiliar with the fandom but curious: it's a webcomic, currently on chapter 35 and if you've got a spare afternoon it's totally do-able to read the whole thing in one go :D
I'd love to see worldbuilding! I'm more curious about the Court than the Forest, just because I adore urban fantasy/sci-fi settings and it's so vast and full of things that have only been hinted at and I would be thrilled with anything that explored it further, like Kat and Annie having an adventure and solving mysteries and finding - well, anything. I love the robots and the mythological creatures and the ghosts, and I'd love to know more about how the Court fits in with the real world. Annie/Kat would be absolutely delightful, but I'm just as happy seeing them be awesome, adorable friends.
If you want to build on something already established in the comic, I'd love to see futher adventures of the Spacemonauts! or tell me what happened in Chapter 12a: Cursed Teapot Woes. A fairytale fusion or complete AU would also be amazing!
Any other characters you want to include would be very welcome (I started listing people but, er, basically everyone is my favourite!), or something that simply focuses on Annie & Kat's relationship (as friends or more) would be just as wonderful.