It could be a female Namekian. Since Namekians are also very strong and have their own unique culture, a female Namekian could catch Goku's eye. They might bond over their mutual respect for life and their experiences with fighting powerful foes.
In a Goku Black - Justice League fanfiction, it's possible that Goku Black would initially be seen as a threat. But if there was some sort of deal or situation that made him side with the League, he could add a whole new level of power. His fighting style, which is very different from the traditional Justice League members, could make for some exciting battle scenes. He might even teach the League some new combat techniques.
Goku could teach Naruto how to fight without relying too much on ninjutsu. Goku mainly uses his physical strength, speed, and ki in combat. Naruto could learn to better use his own physical abilities, like hand - to - hand combat and quick dodges, which would make him a more well - rounded fighter.
If Goku travels back in time, his relationship with Bulma could be very different. In the past, she was more of a guide to him. But if he goes back with his current knowledge and power, he could become more of a protector for her. He might also be able to prevent some of the dangerous situations she got into in the original story.
One idea could be a crossover with the Naruto universe. Goku with his Ultra Instinct could face off against Naruto in his strongest form. They might start as rivals but then realize they have a common enemy and team up. The story could explore how their different fighting styles and powers interact.
Maybe Goku accidentally saves a female alien during one of his adventures. She is from a race with unique powers. She becomes intrigued by Goku's strength and simplicity. As she stays around to learn more about Earth and Goku, they start to fall in love. Their relationship could be tested by the fact that she has responsibilities in her own world.
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.