A third plotline could be Snape falling in love during his time as a Death Eater. He meets a witch in Voldemort's inner circle who is also having doubts about their loyalty to the Dark Lord. They bond over their shared misgivings and a desire for something more than the life of a Death Eater. Their love gives Snape the strength to secretly work against Voldemort.
Another plotline could involve Kagome and Kouga getting thrown into an alternate dimension where they have to rely solely on each other to survive. This forces them to bond and Kagome realizes she has deeper feelings for him. Maybe they find a magical artifact that can only be activated by true love, and when they hold it together, it starts to glow, revealing their hidden feelings.
One possible plotline could be exploring Snape's internal struggle as he endures Lily's bullying. He might be torn between his feelings for her and the pain she causes. Another could be Lily's realization of her wrongdoings and her journey to make amends.
A great plotline could be Snape training Draco in advanced potions and magic that are not part of the regular Hogwarts curriculum. This could lead to Draco having unique skills that help him in the wizarding world. Also, Snape might take Draco on secret excursions to learn about the history of the Dark Arts in a way that doesn't lead him down a dark path but rather makes him understand the dangers better.
Well, in some fanfictions, Snape might be trapped in a magical trap set by Death Eaters who are still loyal to Voldemort's ideals. Harry, with his natural sense of justice and his loyalty to Hogwarts (where Snape also has a complex connection), figures out the trap's mechanism and manages to free Snape. Or perhaps Snape is on the verge of being attacked by a magical creature, and Harry, using his experience with magical creatures from Hagrid's teachings, scares the creature away and saves Snape.
A great plotline is when fanfiction delves into how Snape's relationship with Lily affects his interactions with the Marauders. Since he loves Lily and she is friends with the Marauders, it creates a complex dynamic. In some fics, Snape might try to protect Lily from the potential harm that could come from the Marauders' more dangerous pranks.
A common plotline is an alternate universe where Snape is not as bitter and Hermione befriends him more easily. They could be involved in a battle against a new dark force, and their combined intelligence and magic powers are crucial for victory. Also, there could be a plot where Hermione accidentally enters Snape's mind through some experimental magic and discovers his deepest secrets, which then changes their relationship.
Well, a plotline might involve Snape's past relationships. Maybe he had a friendship in his youth that was misjudged by others. In the fanfiction, this could be explored, and it could be revealed that he was always a good person deep down. He could also be involved in a plot where he helps to reform Hogwarts' curriculum to be more inclusive, which would show his good - natured side.
Perhaps a plotline where Snape's heart leads him to question his loyalty to Voldemort. As he becomes more in touch with his emotions, he realizes the true horror of the Dark Lord's actions. This could lead to him secretly working against Voldemort in a more direct way than in the original story. He may also find himself in the middle of a moral dilemma as his new - hearted self clashes with his past actions.
One plotline could be that Snape and McGonagall discover a hidden threat against Harry early on. They decide to secretly train Harry in advanced magic that neither Voldemort nor his Death Eaters know about. Snape might use his knowledge of the Dark Arts to teach Harry how to counter the most dangerous curses, while McGonagall focuses on strengthening Harry's Transfiguration skills to help him in combat and escape situations.
One interesting plotline could be Severus Snape as the Dark Lord secretly working to undermine the true evil forces from within. He might be using his double - agent skills in a new way, playing both sides not just between the Order of the Phoenix and Voldemort, but among different factions of dark wizards. For example, he could be preventing more heinous acts that would lead to the total destruction of the wizarding world while still maintaining his dark facade.