One idea could be that they meet in a completely unexpected place, like a small European town during a music festival. Bella is there to experience new things after the events in her own story, and Peter is there to escape his past. Their initial encounter is full of tension as they sense something different about each other. Another plot could involve them having to work together to solve a mystery that involves both the vampire and human worlds. Maybe a new type of vampire is emerging that threatens both, and they must combine their unique skills and knowledge to stop it.
The Volturi could be main antagonists. Since they have strict rules about vampires and humans, they might see Bella and Jasper's relationship as a threat to their order.
There are definitely some out there. It really depends on what you're looking for in a fanfiction. If you like adventure - filled stories, you might find ones where they go on some sort of quest together. Or if you prefer more of a romantic angle, there could be fanfictions exploring their potential romantic relationship, but keep in mind that this is a fan - created concept and not part of the official canon.
One idea could be that Jasper and Bella discover a unique bond that helps them face the challenges in the vampire - human world together. For example, Bella's unique ability to resist vampire powers in the original story could be enhanced when combined with Jasper's gift of manipulating emotions.
One common theme is the exploration of the supernatural world from their perspectives. Since they are from the vampire - related universe, many fanfictions delve deeper into the rules and mysteries of that world.
In fanfiction, their relationship might develop through a series of adventures. Suppose they go on a quest to find a rare artifact that has the power to either save or destroy the vampire world. Along the way, they face numerous challenges like dangerous terrains and other powerful vampires. During these hardships, they start to care for each other more. Peter might show his protective side towards Bella, and Bella might be the one to give Peter hope and a new perspective on life. This would strengthen their bond.
One common theme is the exploration of an alternative relationship. Since in the original Twilight story, Bella is mainly with Edward, fanfictions often explore what could be between her and Jasper. Another theme is Jasper's past and how it affects his relationship with Bella. His experiences as a vampire in different eras are often delved into.
In Jasper Whitlock and Bella Swan lemon fanfiction, the writers usually try to add their own spin to the relationship between the two characters. They might explore Jasper's vampire nature in relation to Bella's human allure in a more explicit way compared to the original story. This can be interesting for some readers who are looking for a different take on the characters. However, it's also a genre that can be polarizing. Some people love the creative liberties, while others prefer to stick to the more traditional interpretations of the Twilight saga.
I'm not sure who the 'best' is as it's subjective, but some popular authors might be those who have a large number of followers and positive reviews. You can check on fanfiction platforms like FanFiction.net or Archive of Our Own to see which authors are highly rated for their Jasper and Bella stories.
In major jasper whitlock and bella swan fanfiction, a frequent theme is the struggle between good and evil. Jasper has his past as a Confederate soldier which can be seen as a darker part of his history, and Bella represents a more innocent, good side. Their relationship can be a battleground for this struggle. Another theme is the concept of family. How Bella fits into the Cullen family with Jasper being part of it is often explored. And finally, the theme of sacrifice. How far will Jasper or Bella go to protect or be with the other is a common exploration in these fanfictions.