This topic is for those uncommon ships that just don't have enough stories written about them to warrant their own topic!
This recommendation is a gift for PaulaTheProkaryote for the Pass It Along Challenge, with love from EugeniaTheEukaryote.
Title: The Darkest Hour
Link(s): HPFF | AO3
Length / Completed: One-Shot, 2500+ Words, Complete
Additional Pairing(s): Sirius Black/Petunia Dursley (née Evans), Vernon/Petunia
Genre(s): Drama, Horror/Dark, Romance
Reasons for recommending: Well-written and very unique - not only with its pairing choice, but also its descriptions of life inside Azkaban and the plot itself. Paula captures the fragile relationship between two trapped people who find a bit of freedom in each other.