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.
A fanfic could explore a friendship between Boa Hancock and Domino. For instance, Domino visits Amazon Lily and is initially met with suspicion but through her interactions with Hancock, they develop a bond. They could exchange stories about their different experiences in the world.
A common theme is her beauty and the effect it has on others. Since she is known for her stunning looks in the One Piece world, many fanfictions play with this aspect, like how characters react when they first see her.
A plot could be centered around a competition. There's a grand tournament in the One Piece world and both Boa Hancock and Domino enter. They compete against each other at first but then realize there's a bigger threat behind the tournament and decide to work together to overcome it. This would involve detailed descriptions of their battles during the tournament and their changing relationship.
The theme of self - discovery can also be present. Hancock might discover new sides of herself because of her relationship with Luffy. For example, she could become more open - minded or learn to trust others more, which is a big step for her as the empress of Amazon Lily.
Another angle could be a romantic relationship between them. It would be interesting to see how their relationship develops, considering their different backgrounds. For example, Robin's past with the Straw Hats and Hancock's role as a Shichibukai. Their relationship could bring out new sides of their characters that we haven't seen before in the original story.
A big theme is also about breaking barriers. Hancock is a proud and strong woman from Amazon Lily, and Luffy is a carefree pirate. Their relationship in fanfics often shows how they break cultural and social barriers between them. For example, Hancock's tribe has certain traditions and views about men, but with Luffy, she defies some of those. Also, friendship is a theme as Luffy values friendship highly and Hancock becomes part of his circle of friends in a special way.
A possible fanfiction could be about Naruto and Boa Hancock teaming up to rescue their respective friends. Naruto wants to save his comrades from a powerful enemy in the Naruto world, while Hancock aims to free her sisters from the clutches of a new and menacing pirate group. Together, they use their combined strength, Naruto's Rasengan and Hancock's petrifying gaze, to take on their foes and achieve their goals.