There might be a fanfiction where Voldemort discovers Snape's true loyalty is not fully with him. This could lead to a really tense showdown between them. Snape would have to use all his skills in magic and deception to survive. Maybe he has to convince Voldemort that he was only pretending to be against him to gain more information for the Dark Lord.
There are fanfictions that explore Snape's relationship with Voldemort in a more psychological way. For example, delving into how Snape's past experiences with Voldemort shaped his actions throughout the series. Maybe Snape has to face some of his darkest memories related to Voldemort and overcomes them in a unique way in the fanfiction.
Another interesting plot could be a backstory about how Snape first got involved with Voldemort. Maybe it was out of a thirst for power initially, but then his views changed over time. This could be delved into in great detail, showing his transformation from a potential dark wizard follower to a hero in the fight against Voldemort.
One possible reason could be that Snape fails to deliver crucial information. Voldemort is a very demanding and unforgiving master. If Snape doesn't give him accurate details about the Order of the Phoenix's plans, for example, Voldemort would surely be enraged and punish him.
The main thing that makes Snape vs Voldemort fanfiction interesting is the contrast between the two characters. Snape is complex, with his own motives and a hidden side. Voldemort is pure evil. So when they interact, there are always mind games and power plays. For example, Snape has to constantly deceive Voldemort, and the tension this creates is exciting.
One interesting plot idea could be that Snape discovers a hidden weakness of Voldemort. Maybe it's a long - forgotten spell that can counter Voldemort's most powerful dark magic. Snape, using his extensive knowledge of the dark arts and his own skills as a wizard, decides to face Voldemort alone to end the reign of terror. Another plot could involve Snape having to team up with some unexpected allies, like a group of students he has been secretly training, to take on Voldemort.
One plotline could be Snape trying to outwit Voldemort in a battle of wits without Voldemort suspecting his true loyalties. It would be full of tense moments as Snape has to be very careful with his every move and word.
In some fanfictions, Snape might be working with Voldemort because he has been blackmailed. Voldemort could have found out some deep, dark secret about Snape and is forcing him to cooperate. This could be related to Snape's past or something he has done that he doesn't want to be made public.
These fanfictions usually create a different view of Snape's character. His loyalty to Voldemort can make him a more calculating and cold - hearted figure. They might also introduce new plotlines that involve Snape's role in Voldemort's plans, like how he might manipulate other characters to serve Voldemort's goals. This can lead to a re - evaluation of the other characters' relationships with Snape as well.
One interesting fanfiction could be about Harry and Voldemort having to team up to face a new, even greater dark threat. This would completely turn their usual dynamic on its head.
In voldemort wins fanfiction, there might be a lot of character development that goes against the original. For instance, some of the Death Eaters could become more complex characters. They may start to question Voldemort's extreme rule once they see the destruction it causes. Also, there could be a different take on the prophecy and how it was misinterpreted which led to Voldemort's win.