I don't recall ever seeing this period explored in fanfiction, though it's entirely possible that I'm just missing a few well-known stories. I feel like you could probably do a lot with it too, considering how much tension probably lingered after the first war.

To clarify just in case, the time period in question is between the First Wizarding War and Harry Potter coming to Hogwarts, so from 31st of November, 1981 to 1st of September, 1991. Besides that, anything goes. It could be a character we know like the older Weasley brothers, it could be an OC. It could be Hogwarts-centric, it could be about the Malfoys rebuilding after the war for all I care. So long as it's written at least decently.

 

Black & White by our very own Sesc takes place immediately post-war.

 

There are a few Remus-centric fics set in his "missing years", which is essentially the period you're looking for:

Carnival of Dark and Dangerous Creatures

Sweet Home

Under Pressure is great one about Snape and his relationship with Dumbledore following the first war.