One idea could be that Goku arrives in the Pokemon world by some sort of interdimensional rift. He might be confused at first but then start to explore the concept of Pokemon battles. He could use his martial arts skills to train Pokemon in a unique way, like teaching them special combat moves. For example, he could train a Pikachu to use a move similar to his Kamehameha, but in a more Pokemon - friendly version, like an electric blast with a similar charging motion.
Goku's power is measured in different forms and levels in his universe. When it comes to Legendary Pokemon, some of them have the ability to control elements like time and space. In a fanfic, Goku in his Super Saiyan Blue form might be able to match the power of a Legendary Pokemon like Palkia, which has power over space. But it also depends on the situation. If Goku is in an environment where his Ki attacks are less effective, like in a dimension where psychic powers are dominant, he might have a harder time against a Legendary Pokemon like Lugia. Overall, it's a complex comparison as their powers are quite different in nature.
One interesting crossover could be a battle between Goku and a powerful Pokemon like Mewtwo. Goku's martial arts skills against Mewtwo's psychic powers would make for an epic showdown. Another could be Goku training with Pokemon to increase his speed and agility. For example, he might train with Pikachu to learn quick dodging techniques.
One of the most popular pairings is Goku with Mew. Mew is this mysterious and all - powerful Pokemon. When combined with Goku's power, there are so many possibilities for the story. They could go on adventures together, exploring new dimensions or facing off against powerful villains. Also, Goku and Lucario are often paired because Lucario has a sense of honor and combat skills that can be compared to Goku's martial arts.
Honestly, comparing the strength of anime Goku and manga Goku is tricky. Both versions have their unique strengths and challenges depicted differently, making it hard to make a clear-cut comparison.
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.