I'm replaying Days Gone (2019 game for ps) and working on Steddie fic, so guess what?
I'm presenting you Steddie Days Gone AU!
Eddie is a member of Hellfire motorclub. He accidentally meet Steve, a hight school teacher, who's car broke down on the road. He helps him and they started dating. Their relationship pissed off most in their circles, both MC and Steve's relatives, so when they're getting married, there almost nobody there to celebrate it, but they don't care.
Then, at some point there's a zombie virus outbreak and Steve got stabbed in the commotion, so Eddie has to put him on the chopper to save his life, while staying to help wounded Gareth (he's Boozer in this scenario I guess) to get out of the town. They got separated.
Two years later Eddie and Gareth still ride together, both convinced Steve's dead and Eddie isn't doing too good. Eventually he finds out that Steve could be alive and leaves to find him.
However, when Steve got on the chopper that day, he met Dustin, a genius young man who previously worked in Hawkins Lab on non-military pharmacy project (if you know the plot of days gone, you know how that went out) and they became inseparable.
Steve couldn't find Eddie either, so he had to move on, finding his purpose in helping Dustin. Dustin end up in the military camp (together with Steve of course) where he works on some solution for the virus problem.
They met Dr Buckley here and even tough she has a reputation of a bitch there (mostly for self-defense reasons), Steve quickly becomes friend with her.
Optionally, there could be Jason Carver as the leader of the rippers, who thinks that the virus happened because of the people like Hellfire Mc who praised the devil (in his mind).
As well as El/Jane as Lisa, who ran away from the lab and managed to somehow (wink wink) survive for two years on her own. She could have a storyline with Dustin, where he tried to help her, but was taken away and she was waiting in his house the whole time before Eddie finds her.
Also, the military camp is ran by Brenner or Dr Kay, the Lost Lake camp is ran by Hopper and Murray could be replacing Copeland in this AU.