One common theme is friendship. Since all these characters value their friends highly in their original stories, in fanfiction they often form strong bonds across their different universes. For example, they might fight together against a threat that endangers all their worlds.
One possible plot could be that there is a rift in the multiverse that brings Goku and Luffy together in a strange new world. They initially misunderstand each other and start to fight. As the fight progresses, they both realize that there is a greater threat at hand that is causing the rift. So, they team up, with Goku teaching Luffy some of his combat techniques and Luffy showing Goku the value of friendship and loyalty in a different way.
Sure. You can check out websites like Fanfiction.net. There are numerous fanfictions featuring these characters. Some might be about epic crossovers where Goku, Naruto, Luffy, and Ichigo team up to fight a common super - powerful enemy. Others could focus on individual character development within the context of their respective universes.
Goku in Ultra Instinct mode is extremely powerful. He has superhuman speed, strength, and can dodge attacks effortlessly. However, Luffy also has his own set of amazing abilities like his Gear Fourth form which gives him enhanced speed and power. But I think Goku would win because his combat skills and power level are just on a different scale compared to Luffy.
Well, Vegeta would be a likely character. He might be initially suspicious of the female Goku. Maybe he thinks she's a threat or just can't believe there's another Goku - like being. He could be there to add some comical moments as he tries to understand the situation.
In general, it's a bit of a toss-up. The strength of Manga Goku and Anime Goku can vary depending on the specific arcs and battles. Sometimes, it might seem like one is stronger in a particular situation, but that could change in another.
The theme of acceptance is quite common. Fem Luffy often has to be accepted by the other characters in the story. This could be because she's different due to her gender or her slightly different personality traits. Also, the theme of self - discovery is prevalent. As fem Luffy navigates the pirate world, she discovers more about herself, her abilities, and her place in the grand scheme of things.