Well, the story could start with the OC finding out she's pregnant and then dealing with the physical and emotional changes. Maybe she has strange cravings that Bucky tries to fulfill in the most endearing ways. There could also be a plotline where they search for a safe place to have the baby, away from the chaos and danger that often surrounds Bucky. They might encounter old enemies or make new allies during this journey, all while preparing for the new life coming into their world.
A possible plot is that the OC discovers she's pregnant at a very inconvenient time, like right before a big mission. She has to decide whether to tell Bucky immediately or wait until after. This could lead to a lot of internal conflict for her. And then, as the pregnancy progresses, Bucky could start to become overprotective, which might cause some friction between them as the OC still wants to maintain her independence.
A possible plot in a Bucky Barnes kidnapped fanfiction could be that Bucky is on a mission for some shadowy organization that wants him to kidnap a person with special abilities. However, once he has the character, he starts to question the motives of the organization. He might see the innocence in the kidnapped character and decide to protect them instead. Maybe the kidnapped character has the power to heal his mental scars from his time as the Winter Soldier. So, instead of delivering the character to the organization, he goes on the run with them, leading to a thrilling adventure filled with action and emotional growth.
One plot idea could be that the OC is initially scared to tell Itachi about the pregnancy. She might worry about how it will affect his mission or his standing in the ninja world. Another could be that Itachi, being the protective type, goes to great lengths to keep the OC and the unborn child safe from his enemies. He might even consider leaving his organization to ensure their safety.
One plot idea could be the OC struggling with the idea of being a mother at a young age while Sasuke is away on a mission. She has to deal with the judgment of the village and her own insecurities. Another could be Sasuke's reaction when he finds out. He might be initially shocked but then become very protective.
One plot idea could be the challenges she faces in hiding her pregnancy from certain characters in the fanfic's world. Maybe there are those who would use it against her or the group she's associated with.
The author can show Bucky's growth by having him initially be hesitant or scared about the pregnancy due to his past. But then gradually, he can become more supportive and protective. For example, he could start learning about pregnancy and parenting, showing his determination to be a good father.
One common theme is the OC helping Bucky deal with his trauma. Given his past as the Winter Soldier, many fanfics explore how an OC with certain skills or a kind heart can aid him in his recovery. Another theme is adventure. The OC might join Bucky on various missions, whether it's related to the Avengers or something more personal. And of course, there's the theme of friendship or romance, depending on how the writer wants to develop the relationship between Bucky and the OC.
One idea could be exploring how Yennefer deals with the physical and emotional changes during pregnancy while still being a powerful sorceress. Maybe she has to find a way to protect her unborn child from the many enemies she has made.
One idea could be exploring how she and her partner (like Percy) adjust to the news. They might have to deal with the reactions of their friends and family. Another could be the challenges she faces during the pregnancy, like her still wanting to be involved in heroic adventures but having to be more cautious.
One idea could be exploring how Gwen's friends and family react to the news. Some might be overjoyed while others could be worried. Another plot could involve Gwen dealing with the physical and emotional changes during pregnancy while also trying to maintain her normal life, like her hobbies or job. And a third could be about the father's role, if known, and how their relationship evolves during this time.
A plot could revolve around Kushina having premonitions about the future of her unborn child during her pregnancy. She might have dreams that she tries to interpret, and this could add an element of mystery. Also, it could be interesting to see how her pregnancy affects her ninja duties, if she has to take a break or if she finds new ways to contribute while pregnant.