Well, a big theme is 'unlikely friendship turned love'. They start as acquaintances or even enemies in some cases, and then their relationship evolves into love. 'Discovering new powers together' is also a theme. As Bonnie has her witch powers and Stefan his vampire abilities, sometimes in fanfictions they discover new ways to combine or enhance their powers when they are together. And 'protecting each other' is a theme that shows their loyalty and deepening bond.
One common theme is friendship. Stefan and Bonnie often start as friends in the fanfictions. For example, they might be friends first and then face challenges that make their bond stronger.
One popular plot twist is when Bonnie discovers she has a hidden connection to both Damon and Stefan's pasts that she wasn't aware of. Maybe she finds out she's related to an ancestor who had a significant role in their vampire - witch history. Another twist could be that one of them is forced to make a sacrifice for Bonnie. For instance, Damon might have to give up his vampire powers to save Bonnie from a dark magic curse.
Another theme is 'redemption'. Stefan has his own dark past, and Bonnie is often portrayed as a powerful and good - hearted character. Fanfics may explore how Stefan can find redemption through his relationship with Bonnie, or how Bonnie helps him overcome his inner demons.
One common theme is love triangle. Since Bonnie, Damon and Stefan are all connected in the Vampire Diaries universe, the love triangle between them is often explored. It creates a lot of drama and tension.
One great Bonnie and Stefan fanfiction is 'A Different Kind of Bond'. It explores their relationship in a unique way, delving into how they might support each other through the various challenges in the vampire - witch world. Another is 'Bonnie and Stefan: The Unlikely Alliance' which shows them teaming up against common enemies and in the process, growing closer. There's also 'Stefan and Bonnie's Hidden Journey' that takes readers on a journey of discovery as they find new aspects of their connection.
One popular theme is redemption. Kai is often a character in need of redemption, and in many fanfictions, Bonnie becomes the catalyst for that change. Their relationship is explored in the context of Kai trying to make up for his past misdeeds.
One interesting plot could be them dealing with the reactions of their friends. Maybe Damon is initially shocked but then comes around. Another could be Stefan and Bonnie exploring new magical abilities together that come from their union.
Well, for one thing, fans are always interested in seeing different pairings. Bonnie and Stefan each have their own unique personalities and storylines in the original show. When combined in fanfiction, especially with a kiss involved, it creates a whole new set of emotions and plot possibilities. Their different powers and backgrounds can lead to really interesting interactions that draw readers in. Also, it gives fans a chance to rewrite or expand on the story in a way that satisfies their own desires for the characters' relationships.
One challenge could be the reaction of their friends. Some might be supportive, but others could be judgmental or think they're not ready. Another challenge is dealing with the physical and emotional changes during pregnancy. Bonnie would have to deal with morning sickness, mood swings, etc. and Stefan would need to be understanding. Also, they might face financial difficulties in preparing for the baby.
One possibility could be that they start off as friends. Maybe they are on a dangerous adventure together, and in a moment of extreme closeness and shared vulnerability, their feelings turn romantic and lead to a loving encounter.