I've done a bit of market research when looking at other people by searching 'fanfiction'. Within large fandoms, a lot of people enjoy reading alternative plots/a build on from the original and a lot of the time can't find one that matches their fandom. In the long run, it probably wont be such a good idea due to fandoms slowly declining over time and slowly decreasing in understanding with what I'm working with. For the time being, I want to do fanfiction and other stories because I find writing fun but I don't have very strong starting ideas.