One great Severus Snape and Ron Weasley fanfiction is 'The Unlikely Bond'. In this story, Snape and Ron are forced to work together on a dangerous mission in the Forbidden Forest. It shows how their initial animosity slowly turns into respect as they face various magical creatures and dark magic threats. Another interesting one is 'Snape's Surprising Ally'. Here, Ron discovers a side of Snape that no one else has seen when he stumbles upon Snape's secret research. This leads to a series of events where they have to rely on each other.
There's a fanfiction called 'Ron and Snape: A Magical Connection'. It's set after the war. Ron, who is now working in the Ministry, has to deal with some old potions-related mysteries that only Snape can help with. Their interactions are full of tension and grudging admiration. It also delves into Ron's growth as a wizard and Snape's complex post - war identity.
Another great one is 'Ron and Snape: An Unlikely Pairing'. This fanfiction focuses on how Ron's carefree nature starts to chip away at Snape's cold exterior. It has some really well - written character development and some great dialogue between the two characters.
One common theme could be the exploration of an unlikely relationship. Since Snape and Ron have very different personalities in the original story, fanfiction might focus on how they overcome their differences. Another theme could be the power dynamic, as Snape is a teacher and Ron is a student, which can add an interesting layer to the relationship in the fanfic.
One common theme is redemption. Snape is often portrayed as a character in need of redemption in these fics, and Ron can be the catalyst for that change. For example, Ron might see past Snape's harsh exterior and actions in the original series and help him become a better person.
I'm not really into that particular slash fanfiction myself, but you can try searching on fanfiction.net or Archive of Our Own (AO3). They have a vast collection of Harry Potter - related fanfictions, and you might be able to find some Severus Snape and Ron Weasley ones there.
One great Severus Snape and Lily fanfiction is 'The Prince's Tale Revisited'. It delves deeper into their relationship, showing Snape's unwavering love for Lily even in the face of her friendship with James. Another is 'Lily's Perspective' which gives an interesting take on how Lily might have truly felt about Snape throughout their years at Hogwarts. And 'Snape's Memories of Lily' is also a good one as it explores the memories that Snape held so dear of Lily.
Often, in fanfictions, Ron's loyalty to his friends and Snape's knowledge of the Dark Arts create an interesting dynamic. Snape may be reluctantly impressed by Ron's courage, which is something he secretly admires in Gryffindors. And Ron might come to realize that Snape is more than just the mean professor he thought he was. There are also fanfictions where they are paired up for a difficult class project, and through that, they start to understand each other better.
One good Severus Snape sick fanfiction is 'The Illness of Severus Snape'. It delves into his inner turmoil as he battles an unknown sickness while still trying to maintain his duties at Hogwarts. The author does a great job of showing his vulnerability, which is a side we don't often see in the original books. It also has some heart - warming interactions with his students who start to see him in a different light.
One great Severus Snape fired fanfiction could be 'The Aftermath of Snape's Dismissal'. It might explore how Snape copes with being fired from Hogwarts. He could be forced to find new allies in the wizarding world outside of the school. Another could be 'Snape's New Beginning' which delves into his journey to redeem himself after the unjust firing.
There's also 'Snape: The Hidden Healer'. This one is interesting as it focuses on Snape's knowledge of potions and magic being used for the care of others. It shows a side of him that is often overlooked, his ability to heal not just physical wounds but also emotional ones, through his gruff exterior.
There's a fanfiction called 'Snape and Malfoy: A Different Path'. It presents an alternate universe where Snape and Malfoy's families have a closer connection from the start. This causes them to grow up together in a different way, and the fanfiction explores their evolving relationship that has elements of romance. It's interesting to see how the author plays with the canon elements of the Harry Potter universe to create this unique story.