tbh i don't read (let alone write) much fanfiction nowadays, but one type of fic that is and will always be a guilty pleasure of mine is basically "replace the characters from [piece of media a] with suitable(?) characters from [piece of media b]", which means i'm always mentally coming up with choni au fic ideas based on media other than riverdale that i like.
some of these might make more sense than others, and i'll admit that they'd all be more for my own self-indulgence than anything else, but i'll still leave them below and update this post as i get more ideas (btw if anyone is interested on any of these, let me know and i might actually try to write it!).
jennifer's body: (closeted) cheryl is jennifer, toni is needy (possibly nerd!toni just cause she's cute), nick is nikolai, fangs is chip, jughead is colin, archie (or reggie) is jonas. all the guys (including nick and his band, eventually) would still die, but choni would get a happy ending (in short, cheryl lives and they end up together).
suspiria (2018): cheryl is susie, toni is sara, (older) heather is madame blanc, everyone else is tbd. cheryl and toni would be more explicitly a couple throughout the fic, toni would survive, and they'd very much end up together. ps i know most(?) people like susie/blanc, but i prefer susie/sara, so that's what i'd write the fic based on. sue me.
ready or not: toni is grace, cheryl is daniel, julian (or some blossom sister oc if we wanna keep it gay through and through) is alex, clifford is tony, penelope is becky, polly is emilie, jason is fitch, minerva (or heather) is charity, claudius (or maybe nana rose, or one of those other blossom relatives whose names i can't remember right now) is aunt helene. the attraction between cheryl and toni would be at least somewhat more explicit, and they'd somehow both end up alive and together (or on their way to being together, at least).
mamma mia!: toni is donna, anthony is sophie, cheryl is sam (which makes sense because i say so and because *insert some soulmate crap here*), fangs is bill, kevin is harry, veronica is tanya, betty (or tabitha) is rosie, and idk who anthony's boyfriend/fiancé is, but it's not the "canon" one cause that whole storyline gave me the ick.
a star is born: cheryl is jackson, toni is ally, everyone else is tbd. it'd have a happy ending (again, in short, cheryl lives and choni stays together), but still be angsty up until that point.
all cheerleaders die (2013): cheryl is maddy, toni is tracy, heather is leena, nick(?) is terry, polly is martha, betty is hanna, veronica is alexis. ps yet again, i know maddy/leena is what's canon in the movie, but i prefer maddy/tracy, so that's what the fic would be inspired by.
bonus ideas (aka stuff that wouldn't be specifically focus on choni but could still end up including it):
black swan: betty is nina, veronica is lily, alice is erica, everyone else is tbd. ps this one could technically also work for choni, but something about it feels more beronica for some reason?
