One idea could be that Bella, instead of becoming a vampire, is bitten by a zombie. She then has to struggle with her new zombie nature while still holding onto her humanity. For example, she might try to resist the urge to attack her human friends like Jacob and Charlie.
Well, perhaps in the fanfiction, the SAS discovers a portal that leads to a different dimension full of zombie - like creatures but with unique abilities. They then have to use their military skills combined with the knowledge they gain from the new environment to survive and close the portal. They could encounter some local resistance fighters in that dimension who are also trying to fight the zombies, and they all join forces.
One idea could be that Bella, with her unique ability to attract vampires in her original story, has an unexpected reaction to the zombies in The Walking Dead universe. Maybe her scent or some hidden power she has confuses the zombies, leading to some comical or strategic situations for her group.
One plot idea could be that Bella and Zach get into an argument over a football strategy, but then they realize they both have the same goal and end up working together better than ever. Another could be a situation where Zach gets injured and Bella has to step up to help him both in his recovery and on the football field. Maybe they also go on a double date with their friends and some comical misunderstandings occur during the date.
One idea could be that Bella and Hunter get into an argument over a football strategy, but then realize they both have the same goal of winning the big game and end up working together better than ever. Another could be a situation where they accidentally get locked in the school gym overnight and have to rely on each other to get out and also face their feelings for each other during that time. Or perhaps they both enter a local talent show separately and then decide to team up at the last minute to create an amazing performance.
One plot idea could be that Bella is transported into the Cinderella story. She uses her modern - day knowledge to help Cinderella in a new way, like teaching her self - defense so she can stand up to her step - sisters. Another could be that Cinderella has some of Bella's traits, like being a bit clumsy at times but still having a heart of gold. A third idea is that Bella discovers that Cinderella's fairy godmother is actually a powerful witch from her own world, and they have to team up to defeat an evil force that threatens both of their worlds.
One idea could be a time - travel plot. Tinga Bella could travel back in time to a key moment in her world's history and have to make choices that change the future. Another could be a crossover with another fictional universe, where she meets new characters and has to adapt to a different set of rules. Or perhaps a story where she loses her powers temporarily and has to rely on her wits and the help of her friends to overcome a powerful enemy.
One idea could be that Bella discovers she has a special power that only she can use to protect the wolf pack. For example, she might be able to communicate with the spirits of the forest which give her warnings about upcoming threats.
One idea could be Bella has a unique power that the Avengers need to defeat a new, powerful enemy. For example, she can manipulate time briefly, which is crucial in a battle against a villain who can freeze time for long periods. Another could be Bella being from an alternate universe and she has to team up with the Avengers to stop the merging of her universe with theirs which would cause chaos. Maybe she has knowledge of a magic that the Avengers have never encountered before.
One idea could be that Sam and Bella discover a hidden magical realm together while on a hike in the forest. They have to work together to find their way out and in the process, they learn more about each other's fears and hopes.
A possible plot is that Bella decides to get a tattoo in a world where tattoos are frowned upon in her community. This causes a rift between her and her family or friends at first. But then she meets a group of people who also have tattoos and they introduce her to a whole new subculture. Through this, she discovers more about herself and what she really wants in life, and has to decide whether to stay with her old life or fully embrace this new one.