A really cool fanfiction could be set in an alternate universe where Harry, Snape, and Draco are all part of a secret society in Hogwarts. They have to keep the society's existence and purpose a secret while dealing with their own personal issues and rivalries within the group.
There are fanfictions that explore a different side of the relationships. For example, a story might show how Lucius and Snape were once friends in their youth and how that affects their interactions with Harry and Draco later. Maybe there's a plot where Draco starts to question his family's values after getting to know Harry better, and Snape has to navigate this complex situation to keep the peace in Hogwarts. There could also be a time - travel fanfiction where Harry goes back in time and has to deal with a younger Snape, Lucius, and Draco all at once.
One interesting Snape and Draco fanfiction is 'The Mentor and the Student'. In this story, Snape takes Draco under his wing in a more in - depth way than in the original books. It shows their complex relationship evolving as Draco struggles with his family's expectations and Snape tries to guide him towards a different path.
There might be a fanfiction where Snape discovers a young Draco has a unique magical ability that he decides to secretly train. This could lead to a series of adventures where they have to hide this from Lucius and other Death Eaters. It could explore Snape's conflicted feelings as he tries to protect Draco while also being in a difficult position within the Death Eater ranks.
One interesting Snape and Harry fanfiction could be one where Snape mentors Harry in a more private and less hostile way. They could bond over potions and Snape could finally see Harry as more than just James Potter's son.
One interesting Harry Snape fanfiction could be one where Snape adopts Harry after the death of his parents. In this story, Snape has to overcome his initial dislike for James Potter's son and gradually forms a unique bond with Harry. It shows a different side of Snape, his capacity for love and care that was hidden beneath his cold exterior in the original series.
One interesting Snape - Harry fanfiction could be where Snape finally reveals his true feelings about protecting Harry to him. Maybe in a moment of danger, Snape confesses that he was always secretly looking out for Harry because of his love for Lily.
One unique plotline is when Snape has to train both Draco and Harry in a special form of magic that was lost for centuries. This brings out a whole new side of their relationships as they have to rely on each other to master the magic. It's different from the usual Hogwarts drama we see in the books.
Some fanfics have a plotline where Draco becomes a double agent, and Snape has to protect him while also dealing with Harry's suspicions. It creates a really tense and interesting dynamic between the three.
One great fanfiction could be 'The Unlikely Alliance'. In this story, Harry, Snape, and Draco are forced to work together during a time when Hogwarts is under a new and mysterious threat. It shows a different side of their relationships as they learn to rely on each other's strengths.
One interesting deaged Snape and Harry fanfiction could be about Snape being deaged to Harry's age and them having to work together on a special project at Hogwarts. They might start to see each other in a new light, away from their usual teacher - student dynamic.