Yes, there are. The Stranger Things comics offer additional adventures and backstories that complement the TV series. They provide more depth to the Stranger Things universe.
Well, time travel is a cool theme. Some fanfictions might have the characters going back in time to prevent certain events in the show from happening, like the opening of the gate to the Upside Down. Then there's the theme of alternate universes. Imagine a universe where Eleven was raised by Brenner in a completely different way. And of course, the theme of romance. You can find a lot of fanfictions about Mike and Eleven's relationship, but also other possible pairings among the characters.
No. While 'Stranger Things' has a very immersive and believable world, it is all made up. The characters, the small town of Hawkins, Indiana, and the strange happenings there are products of the writers' imaginations. The show uses nostalgia for the 80s to create a unique atmosphere, but it has no basis in real - world events.
Definitely fiction. Stranger Things has elements like monsters and alternate dimensions that are not real. It's created for entertainment purposes and doesn't represent real-life events or people.
Stranger Things is not based on a comic. It originated as an idea from the minds of the creators and developed into the popular series we know today. The show has its unique characters and plotlines that aren't adapted from comic material.