One common theme is the clash of different power systems. Star has her magic from the 'Star vs the Forces of Evil' universe, and Goku Black has his Saiyan powers from Dragon Ball. Another theme could be the exploration of good and evil. Goku Black is a villain, so stories might focus on how Star and her friends deal with his malevolence. Also, the idea of interdimensional travel can be a theme, as Goku Black is from a different universe in Dragon Ball and would have to cross into Star's world.
Well, I don't have a specific title off - hand. But a good place to start looking for 'Star vs the Forces of Evil Goku Black' fanfiction is Archive of Our Own. They have a wide range of fan - created works. You can filter by the relevant fandoms and look for stories that incorporate both elements in an interesting way, like maybe a story where Goku Black ends up in the dimension of 'Star vs the Forces of Evil' and causes chaos.
Well, 'perfect cell crossover fanfiction' could be about taking the character of Perfect Cell from Dragon Ball Z and crossing him over into different universes or storylines within the fanfiction world. It might involve him interacting with characters from other anime or even creating new scenarios and power - level battles.
One possible storyline could be that Goku is accidentally transported to Alucard's world. They start off as enemies but then gradually learn about each other's powers and come to respect one another. Another could be that a powerful villain manipulates them into fighting each other. In this case, they might realize they are being used and team up against the real enemy.
It's really hard to say. Goku is extremely powerful with his Super Saiyan forms and incredible combat skills. But Alucard has his vampiric powers like immortality and the ability to control shadows. In a fanfic, it could go either way depending on how the author wants to write it. Maybe if the author wants to emphasize speed, Goku might have an edge. But if it's about dark, mysterious powers, Alucard could come out on top.
Well, perhaps in this fanfiction, Goku Black makes a fatal mistake. He could underestimate Goku's ability to adapt during battle. Goku, being the experienced fighter he is, notices this weakness and uses it against Goku Black. He might use a combination of his signature moves like the Kamehameha in a new and unexpected way that catches Goku Black off - guard, leading to his defeat.
Well, in fanfiction, if Goku Black fuses with Goku, it could result in a super powerful being. Their combined powers might create a new form with an extremely high power level. This new entity could have a mix of Goku Black's dark and devious nature with Goku's pure-hearted heroism, leading to an internal struggle within the fused form.
The story could start with Goku being pushed to his limits by Goku Black's attacks. But then, he remembers his training with the Kai's and how they taught him to focus his energy in a more efficient way. He then uses this knowledge to create a more powerful Kamehameha that breaks through Goku Black's defenses and kills him.
If Goku Black fuses with Goku in fanfiction, the story would progress in a complex way. The fused form might go on a journey to understand itself. Since it has two very different personalities combined, it would face a lot of internal conflict. This could be used to explore themes like identity and the struggle between good and evil. Externally, the fused Goku could attract new enemies who see it as a threat to their power or plans.