There are all sorts of mods out there that bring a little bit of other worlds into Skyrim. Some of these come from movies, books, television shows, other video games (ESO has it’s own mod category, so it is not included here), and more. Here is an assortment that I have found; I have only tried some of these, so as always, read descriptions and posts on the mod pages. (Keep in mind that a lot of these are just for fun, although some fit surprisingly well in the world of Skyrim.)
Please remember to endorse any mods you download and like, and if you appreciate all the hard work that goes into creating a mod, consider giving kudos to the author on Nexus as well (the Give Kudos button can be found on the user’s page).