Whew, trying to pin down where the 'Sofia the First' fandom migrated is like tracking a shapeshifting wizard. The big ones are still Archive of Our Own and FanFiction.net, obviously. AO3 has the edge for tagging and curation, so you'll find the more intricate ship dynamics there—Sofia and Hugo stuff gets really layered. But honestly? I've stumbled upon some surprisingly sweet one-shots on Wattpad, buried under all the teen romance stuff. You just have to sift through tags like #sofiathefirst or #princesssofia. Tumblr's not a hosting platform per se, but it's the engine room for ideas; a lot of writers link their AO3 works from there. DeviantArt still has a pocket of artists who write, but it's more of an archive now. The real shift I've noticed is to smaller Discord servers, where people share Google Docs links—it's more private, less about hits and kudos, more about the craft. It feels like the community got quieter but deeper, you know?
I miss the peak FF.net days around 2015, but the writing's better now. Less 'Sofia gets a new amulet' plots, more character studies of Cedric or Amber.