Well, I've come across a few. Some explore Goku Black's relationship with Goten in really unique ways. For example, there are stories where Goku Black has a change of heart due to his interactions with Goten. It's really fascinating to see how different authors play with their characters' personalities and the overall Dragon Ball universe in these fanfictions.
One common theme is redemption. Goku Black, being a villain, might find redemption through his connection with Goten. Another theme could be power dynamics, as Goten has his own set of powers and how they compare or interact with Goku Black's is interesting to explore.
One possible storyline could be that Naruto is somehow transported to Goku Black's universe. There, he has to face Goku Black who sees him as an intruder. Naruto would have to quickly learn about Goku Black's powers and find a way to fight back using his ninja skills. Another storyline could be that a powerful villain creates a rift between their two universes and pits them against each other. They start off as enemies but then realize they are being manipulated and team up to fight the real villain.
There could be a storyline where Beerus, out of boredom, decides to train Goku Black instead of fighting him. But Goku Black misinterprets this as a sign of weakness and attacks Beerus. This could lead to a battle where Beerus has to hold back at first to avoid killing Goku Black, but as the fight progresses, he realizes he has to use his full power to subdue him.
There might be a fanfiction where Goten gets lost in time, and Goku has to travel through different eras to find him. Along the way, Goku meets versions of his friends from different time periods and has to team up with them to rescue Goten. This would involve a lot of action and emotional reunions.
One possible storyline could be that Goku Black arrives on Earth in search of a powerful energy source. The Justice League detects his arrival and confronts him. At first, they underestimate his power. Goku Black easily defeats some of the members, but then the League starts to work together and figure out his weaknesses. Another storyline could be that an evil entity has brought Goku Black to the DC Universe to cause chaos and the Justice League has to stop him while also dealing with the entity. Or perhaps Goku Black is tricked into thinking the Justice League are enemies of the Saiyans and he attacks them, only to later find out the truth and have to team up with them to fight a greater threat.
The different interpretations of the characters are great. In some fanfictions, Goku Black might be portrayed as even more evil or cunning than in the original series, and Hit could be shown with new strategies. For instance, a fanfiction might have Hit teaming up with other characters from different universes to take on Goku Black, which adds a whole new dimension to the story.
One great fanfiction is 'Goku and Goten's Training Days'. It focuses on Goku teaching Goten new techniques. It's really exciting as it shows their father - son bond through the training sessions.
You can try websites like FanFiction.net. It has a large collection of fan - made stories, and you can easily search for Goku and Goten fanfiction there. Just type in their names in the search bar, and you'll get a bunch of results.