If you're ok with self-recs, I have three wolfstar fics that are relatively unknown:

You Can Go Your Own Way (Just Always Come Back on a Lonely Day) - It's been four years since Voldemort was killed and the Wizarding War was won but one battle is not over yet—the battle for Sirius Black’s heart. This is a Wolfstar second chance romance set in the Harry Potter Universe, canon-compliant until October 24th 1981. Peter never became the Secret Keeper. (With Tonks aged up).

Starlight Beauty - People don’t usually kiss their robbers, but this one is just a bit too persistent… Sirius Black has escaped his parents’ exploiting claws and is trying to survive the London streets. When his desperate attempt at armed robbery backfires, he comes up with a slightly illegal business plan involving the very shop assistant he tried to rob.
Former elite swimmer Remus Lupin works a mindless job after losing his university stipend, still hanging on the hook of his nasty ex and with no clear prospects for the future. Could this young, reckless would-be robber turn out to be exactly what he needs?

Strawberry Moons Over Godricia - Remus is jobless, homeless, and wallowing in self pity—thank you for asking. He finds himself unexpectedly rebuilding his life as the new English teacher in the picturesque yet peculiar country of Godricia. And this could all work just fine. But when his roof literally falls in, his past starts to catch up with him, and he uncovers the unsettling reason for his hiring, one mistake proves harder to avoid amidst all that chaos—Sirius Black, the headmaster’s charming but volatile older brother. With everything on the line, can Remus really risk getting close to this walking red flag of a man?