The list of fandoms I actively participate in have been changing and evolving for well over a decade. As of writing this I'm am highly involved in several particular fandoms. They are: Harry Potter, A Song of Ice and Fire/Game of Thrones, Star Wars, Gone With the Wind, and Jurassic Park. I have other, more minor fandoms, but those are the big ones.
It should be noted I am a big fan of shipping, so don't be surprised if I tend to focus on pairings more than anything else in any given fan base. I am a loooooong time lover of H/Hr from Harry Potter, as well as H/L (Harry and Luna). I adore Anakin/Padmé of Star Wars more than I should, probably. Of course I support Scarlett/Rhett. In Game of Thrones I thoroughly enjoy Arya/Jaqen (if she's properly aged up, I'm not a skeeve), Arya/Jon (dido the former as well), and Sansa/Margaery. Owen/Claire from Jurassic World also has my interest. I have plenty of other smaller ships, particularly in ASOIAF/GOT, but I won't bore you with listing them all.