In these fanfictions, the 'love at first sight' trope can be found. The OC could be immediately smitten by Snape's mysterious aura. Additionally, the 'saving each other' trope is popular. Snape might save the OC from some dark wizard or the OC could save Snape from his own self - destruction. It makes their bond even stronger as they realize how important they are to each other.
A common trope is the 'Injury Reminder'. In these fanfictions, Snape's limp serves as a constant reminder of a past battle or dark encounter. It adds a sense of mystery and danger to his character.
One popular theme is redemption. Snape is a complex character with a troubled past, and an OC can be a part of his journey towards redemption. The OC might see the good in him and encourage him to let go of his grudges and past mistakes.
One popular theme is the unrequited love. Snape's deep, often hidden love for Lily Potter is a central aspect in many fanfictions. Another theme could be redemption through love, where his love for someone helps him overcome his darker tendencies. Also, the theme of forbidden love can be seen, as Snape is a complex and often misunderstood character, and a love story involving him might go against the norms of the wizarding world.
One popular trope is the 'enemies - to - reluctant - allies'. Given their history of animosity, it's interesting to see them pushed into a situation where they have to cooperate. Another is the 'redemption arc' for Snape, and Sirius being a part of that in some way, either by initially opposing it and then coming around, or being a catalyst for Snape's change.
One popular plotline could be Sasha being a new student at Hogwarts who catches Snape's eye in a Potions class. Maybe she has a natural talent for Potions that he can't help but notice. Another could be that Sasha is involved in some sort of mystery at the school, and Snape has to reluctantly work with her to solve it, all while their relationship develops in unexpected ways. A third plotline might be that Sasha is an outsider to the wizarding world but has a unique power, and Snape is tasked with training her, leading to a slow - burning romantic connection.
Another trope is the 'mentor - mentee' dynamic in reverse. Usually, they are both mentors to students, but in some fanfictions, they end up learning from each other. Snape might learn more about emotional openness from McGonagall, while she could learn about some of the darker arts and how to better protect students from Snape. It's an interesting flip of their usual roles.
One popular trope is the 'opposites attract'. For example, an outgoing OC might be paired with a more introverted character from the original series. Another is the 'fish out of water' where the OC is new to the world of showbiz in the Love Stage universe and has to navigate through various challenges. And the 'friends - to - lovers' trope is also common, with the OC starting as a friend to a main character and gradually developing romantic feelings over time.
Rather than focusing on this specific and somewhat unusual type of fanfiction, you might want to explore more general Severus Snape fanfictions. There are many great ones that delve into his character, his relationships in the wizarding world, and his backstory. These can be found by simply searching for 'Severus Snape fanfiction' on popular platforms, which will give you a wider range of engaging stories to choose from.
There's a fanfiction called 'A Different Kind of Love'. In this story, it explores the complex relationship between Severus and Lily beyond just friendship or unrequited love. It shows how their relationship could have developed in an alternate universe. 'Lily's Last Wish' is another one. This story focuses on how Snape deals with Lily's death and how he tries to fulfill what he believes might have been her last wishes. Then there's 'Severus and Lily: The Forbidden Bond' which examines the idea of a deeper, more secret bond between them that was never fully explored in the original books.
One popular theme is his relationship with Lily. Writers often explore how their friendship developed and how her death affected him deeply. Another theme is his role as a double agent. It's interesting to see how he managed to deceive Voldemort while also trying to protect Hogwarts.