One common theme is the evolution of their relationship from rivals to something more. They start as two Saiyans constantly trying to outdo each other, but in the fanfiction, they gradually see each other in a new light.
A third theme could be the support they offer each other. Despite their differences, in the fanfiction world, they often become a source of strength for one another. This is different from their initial relationship where they were mostly at odds. For example, Goku might be there for Vegeta when he's facing a tough decision about his Saiyan heritage, and vice versa.
Many Goku and Vegeta fanfictions explore the concept of power. How they strive for more power, what they are willing to sacrifice for it, and how they handle having great power. This can lead to some interesting moral and ethical dilemmas within the stories.
One common theme is the exploration of their relationship. Since they have very different personalities, it's interesting to see how they interact and grow closer. Another theme is power - how Fem Goku's power, which might be different from the male Goku's in some interpretations, and Vegeta's power combine or contrast.
A frequent theme is the adaptation of their Saiyan heritage in a female context. In many fanfictions, fem Goku and fem Vegeta have to deal with the expectations of being female Saiyans in a way that's different from the male counterparts. Also, there's the theme of self - discovery. They might discover new aspects of their personalities that are related to their new gender identity. It's like they are re - defining what it means to be a Saiyan as a female.
Friendship is often a theme. Despite their differences, they could form an unlikely friendship. In many fanfictions, they might start off as rivals but end up as comrades, much like Goku and the male Vegeta in the original story. And of course, adventure is a big part of it too. They go on quests, fight new enemies and explore new worlds.
The theme of growth is quite prevalent. Both characters grow in different ways. Goku may grow in his understanding of Saiyan culture through his relationship with female Vegeta, while she might grow in her ability to let go of some of her extreme pride. Another common theme is the protection of the universe. They often team up to fight threats to the universe, which shows their sense of responsibility and heroism.
Another theme is friendship and rivalry. Just like in the original stories, female Goku and Vegeta often have a complex relationship. They can be friends who support each other in battles against common enemies, but also rivals who constantly try to outdo each other in terms of power and skill. This dynamic creates a lot of interesting storylines.
The theme of adventure is also quite common. Writers send Goku and Female Vegeta on various quests or battles against new enemies. These adventures not only test their physical strength but also their bond. They might travel to new planets or dimensions, facing all kinds of challenges that bring out different sides of their characters and further develop their relationship.
One common theme is the struggle with their existing relationship. They have been rivals and then friends, so adding a romantic element means they have to deal with new feelings while still respecting their past. Another theme is acceptance, as they come from different backgrounds and have different personalities. They need to accept each other fully in a romantic relationship. Also, there's often the theme of protecting each other not just as comrades but as lovers.
One common theme is the battle of wills. Goku Black and Vegeta are both strong - willed characters, and fanfictions often explore how they clash or come to an understanding.
Themes like friendship evolving into love are quite common. It starts with them being comrades or rivals, and then as the story progresses, their relationship deepens. Another theme is the discovery of new abilities. The female Goku may have different latent powers that are awakened through her relationship with Vegeta. And there's also the theme of family. How their relationship might lead to a new kind of Saiyan family unit and how they would raise their potential children in a different way compared to what we might expect from the original series.