One great fanfiction could be about their adventures on a new island not shown in the original story. Maybe they encounter a powerful and strange new enemy. Luffy's determination, Zoro's strength, and Sanji's culinary skills all come into play in this new situation.
Another theme is rivalry. Zoro and Sanji have a friendly rivalry which can be elaborated on in fanfictions. For instance, they might compete in a friendly tournament on the ship to see who is stronger or more useful in a certain situation.
Well, they could be in a situation where a powerful enemy targets female Luffy specifically because of her unique abilities as a female version of Luffy. Zoro vows to protect her at all costs. This could lead to some intense battles where Zoro has to fight opponents far stronger than him while trying to keep female Luffy safe. Meanwhile, female Luffy could be using her smarts and powers to find a way to defeat the enemy from the sidelines, perhaps by finding its weakness and relaying it to Zoro during the fight.
Their relationship could develop through shared cooking experiences. Since Zoro loves sake and meat, female Luffy could try to cook for him in her own clumsy but endearing way. This could lead to some comical and heartwarming moments as Zoro tries to be polite about her cooking while also teaching her how to make it better. Through these interactions, they could grow closer.
😋I highly recommend One Piece: Replicating Talent from Elbaf to you! This light novel was about a transmigrator in the world of Luffy, Sauron, Ace, and Shanks. Although it was a Doujinshi novel, the plot was very attractive, especially the interaction between the male and female protagonists and the setting of the copying talent. I hope you like this fairy's recommendation. Muah ~😗
Well, in such a fanfiction, there could be various hints. Maybe Zoro's behavior might be more in line with typical female characteristics described in that specific fictional world, like being more empathetic or having different social interactions compared to the original male - character version. But it really depends on how the author has crafted the story.
They might have an epic battle to test Luffy's growth. Shanks could see how much stronger Luffy has become and be proud. Maybe Luffy will show off his new Haki abilities.
In fanfiction, when Sabo and Luffy meet again, they might have an emotional reunion. They could share stories of their adventures since they last saw each other. Sabo might show off his new skills or powers, and Luffy would be excited to see his brother again. They could also plan new adventures together, vowing to face any challenges as a team.