Well, a plot could involve a magical pregnancy. Bonnie's pregnancy might be the result of some ancient magic that she accidentally unleashed. Stefan, being the loving partner, tries to understand this new situation. They could seek help from other supernatural beings, like Caroline, who might offer her support in different ways, such as helping with the pregnancy cravings or protecting them from potential enemies.
One idea could be that Bonnie discovers she's pregnant during a time of great turmoil in the supernatural world. She and Stefan then have to figure out how to protect their unborn child from all the threats. Maybe they go into hiding, and along the way, they face challenges that test their relationship and their will to survive.
One idea could be that the baby has some sort of special power. Maybe it can communicate with the spirits like Bonnie, and this causes both joy and concern for Bonnie and Stefan. They have to protect the baby from those who might want to use its power for evil.
Another plot could involve Caroline's werewolf friend Tyler coming back and being initially skeptical but then becoming a strong support for them during the pregnancy. This could add some drama as there are historical tensions between vampires and werewolves.
One idea could be that Bonnie discovers she's pregnant during a time of great chaos in the magical world. She has to keep it a secret while trying to protect herself and her unborn child from dark forces. Another could be a story where the father of the baby is a mystery, and Bonnie goes on a journey to figure it out all while dealing with the physical and emotional changes of pregnancy.
One idea could be exploring how the other characters in the FNAF universe react to Bonnie's pregnancy. They might be confused, excited, or worried. Another could be the challenges Bonnie faces during the pregnancy, like dealing with her animatronic body limitations.
One idea could be that they face challenges from the supernatural world while Elena is pregnant. For example, other vampires might see the unborn child as a threat or a powerful asset. Another could be that they struggle to keep the pregnancy a secret from their enemies. Stefan would be extremely protective, and Elena would have to deal with the physical and emotional changes while in a dangerous environment.
One idea could be that they struggle with how to tell their friends and family. Since their relationship has had so many twists and turns, they're worried about the reactions. Another could be that they face some kind of supernatural threat to the pregnancy, which adds a lot of drama and action to the story.
Perhaps the fanfiction could explore the challenges they face due to their different natures. Elijah being a vampire and Bonnie being a witch. There could be concerns about the health of the baby, with Bonnie using her magic to ensure a safe pregnancy and Elijah struggling with his vampiric instincts, like the urge to drink blood while being around his pregnant partner.
Well, they could start a new life away from all the chaos. They find a peaceful place where no one knows them and try to raise their baby in secrecy. But then, their past catches up with them. Maybe an old enemy of Kol's discovers their location. Another angle is that the baby has some unique powers even before birth, and this attracts the attention of both good and bad elements in the supernatural world. Bonnie and Kol then have to figure out how to handle this situation without putting their baby in danger.
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.
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.