A really exciting plotline could be that Hermione accidentally alters time in a way that makes Snape the headmaster much earlier. Snape then enlists Hermione's help to modernize Hogwarts' teaching methods. This would bring about a lot of changes in the school, with Hermione having to deal with the traditionalist professors while Snape tries to keep order.
Another plotline might involve Snape discovering Hermione's use of the Time - Turner and initially being suspicious of her motives. But as they interact more in the altered timeline, they end up forming an unlikely alliance. They could work together to uncover a long - buried secret about Hogwarts that was lost in time.
One common plotline is Hermione using the Time Turner to go back and change certain events in the wizarding world. For example, she might try to prevent some of the tragedies that occurred during the war. Another is her using it to relive certain moments with her friends, like spending more time with Harry and Ron in their earlier Hogwarts years.
One plot could be Hermione using the Time - Turner to go back and change Snape's perception of her. Maybe she tries to show him that Gryffindors can be worthy allies. Another could be that Snape discovers Hermione's use of the Time - Turner in a way that wasn't in the original books and they end up working together secretly to stop a new dark threat.
In fanfiction, the Time - Turner can be a tool to bring Hermione and Snape closer. For example, if Hermione uses it to help Snape with a past event, he may start to trust her more. This newfound trust can change their relationship from one of animosity in the original story to a more collaborative and understanding one. They might share secrets and knowledge that they wouldn't have otherwise.
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.
One interesting story could be where Hermione uses the Time - Turner to go back and prevent a major wizarding war from starting. She might change key events in the past that led to the conflict.
One interesting plotline could be Hermione's struggle to adjust to living with Snape. She's used to the warm and inclusive environment of Gryffindor, and Snape's dark and brooding personality makes it a big change for her. Another could be Snape seeing Hermione's potential not just as a student but as a daughter figure, and he starts to teach her advanced magic privately, which in turn helps Hermione to solve some of the school's mysteries.
One interesting plotline could be that Hermione accidentally stumbles upon Snape in a hidden part of the Hogwarts library while researching a very rare and dangerous magic. Snape initially suspects her of snooping for the wrong reasons but then realizes she's onto something important and they end up working together secretly. This would be a great opportunity to explore their complex relationship further, as Hermione sees a different side of Snape and Snape starts to respect Hermione's intelligence more.
One interesting plot could be that they use the Time Turner to prevent a major disaster at Hogwarts that was overlooked in the original story. For example, they might stop a dark wizard from infiltrating the school during an important event.
One plotline could be Hermione discovers a hidden prophecy that involves Snape and Lucius. Another is that Snape has to protect Hermione from Lucius' dark plans. Or maybe Hermione is a mediator between Snape and Lucius in a magical conflict.
A really interesting plotline is when Snape and Hermione are brought together by a time - travel incident. In this scenario, they have to work together to fix the disruption in time, and in the process, they gain a new respect for each other. Also, there are plotlines where Hermione discovers Snape's hidden talents outside of teaching, like his skills in ancient magic or his connection to some long - lost magical artifacts, which leads to an interesting adventure between them.