Another option could be a new character introduced specifically for the fanfiction. This character could be a powerful pirate or a mysterious figure from Hancock's past. He might have a connection to Hancock's family or her position as a Shichibukai. His presence would add an element of mystery and new dynamics to the story, especially in relation to the pregnancy.
The theme of acceptance is also present. Hancock has a rather difficult past and her feelings for Luffy make her question a lot of things about herself. Fanfictions will sometimes focus on how Luffy's simple and accepting nature helps Hancock come to terms with her own identity and insecurities, and how she in turn becomes more integrated into Luffy's world.
There's also a fanfiction where Hancock decides to join Luffy's crew for a short time. This one delves into how the rest of the Straw Hat crew reacts to her presence. Luffy is his usual oblivious self while Hancock tries to fit in but still maintain her regal air. It's really interesting to see how their relationship develops during this time.
One possible fanfic could be about Luffy's brother Ace meeting Boa Hancock. Maybe Ace could be on a mission near Amazon Lily and they cross paths. He could be initially curious about her powers and her reputation as a beauty. Another idea is a fanfic where Hancock falls for Luffy's brother because he shows some of the same fearless and kind traits as Luffy, but in a different way. It could explore how their relationship develops in the complex world of One Piece.
One possible plot idea could be that she discovers she's pregnant during a time of great turmoil in the One Piece world. Maybe she has to hide it at first to protect herself and the unborn child from her enemies. As the story progresses, she might start to consider how motherhood will change her role as a Shichibukai and her relationship with Luffy and the Straw Hats.
Another interesting one is 'Love on the Grand Line: Hancock and Luffy'. It delves deep into the idea of how their relationship could develop. It has some great character development for both of them and shows how their different personalities could come together in a romantic relationship.
It would be cool to include some of the other Shichibukai in a fanfic with Boa Hancock. Maybe Doflamingo, and the fanfic could explore the power dynamics and political intrigue between them as two powerful figures in the pirate world. Their different personalities and goals would make for an interesting story.
Another way is to check out One Piece fan communities on platforms like Reddit or Discord. There are often threads where fans share and recommend good fanfics. You can post a request asking specifically for fanfics about Luffy's brother and Boa Hancock, and I'm sure fellow fans will be happy to help you out.
In fanfiction, Boa Hancock is often depicted as still being extremely beautiful and powerful. Her love for Luffy may be further explored, with different scenarios of how she might express it. She could also be shown as having more complex relationships with her sisters, perhaps mending some past rifts or facing new challenges together.
Well, a fanfiction involving Naruto and Boa Hancock could be really interesting. It might explore how their different worlds collide. Naruto, from a world of ninjas, and Boa Hancock from the One Piece world. Maybe in the fanfic, Naruto could be on a journey that somehow leads him to Hancock's island. And they could form an unlikely alliance against a common enemy.