Perhaps a fanfiction where Vados senses a new threat approaching the universe. She enlists Goku to help her find a way to stop it. Along the way, they encounter strange new races and powers. Goku's simple but powerful approach to fighting combined with Vados' wisdom would make for an interesting dynamic as they search for a solution to this impending doom.
A fanfiction could involve Vados taking Goku on a journey through different timelines to show him the consequences of his actions. Goku would see alternate versions of himself and his friends. This experience could make him more cautious and strategic in his battles back in his own timeline. Vados would be like a guide, teaching Goku about the importance of balance and how his power affects the multiverse.
Friendship is also a common theme. Despite coming from different worlds, Naruto and Vados in these fanfics usually form some kind of bond. They learn from each other and support one another through various challenges, whether it's fighting a common enemy or just understanding each other's cultures.
There's a fanfic called 'The Meeting of Naruto and Vados'. This one delves into how Naruto, with his ninja skills, and Vados, with her angelic abilities, interact. It's really interesting as it shows Naruto being in awe of Vados' power at first and then gradually learning from her. They end up having a great friendship and going on various adventures together.
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.
Another possible main character could be the villain that forces the two Gokus to meet. This villain could be a new, super - powerful threat that the two Gokus need to deal with. Their meeting becomes a crucial part of the story to defeat this powerful foe.
One of the characters who could betray Goku is Piccolo. Although they've been allies for a long time, in fanfiction, things can change. Perhaps an ancient evil force takes control of Piccolo's mind and makes him turn on Goku. Or it could be Krillin. He might be influenced by an outside force that convinces him Goku is becoming too dangerous. Also, don't forget about the Kais. If there's some sort of power imbalance or a threat they perceive from Goku, they might betray him to maintain the order of the universe in the fanfiction.