Perhaps a plot where they are transported to an alternate dimension where their relationship is completely different. They have to work together to find a way back home while also dealing with the changes in their bond in this new world. For example, in this dimension they might be enemies at first but gradually realize they need each other.
One idea could be exploring a time when Sanzo loses his memory and Goku has to help him remember who he is and their mission. This would create a lot of emotional moments as Goku tries to jog Sanzo's memory with their shared experiences.
Goku can be developed by giving him more complex emotions. In fanfiction, he could struggle with feelings of jealousy if Sanzo spends more time with another character. This would not only add depth to Goku's character but also test his relationship with Sanzo.
One interesting aspect could be the exploration of their relationship in different settings. For example, in a post - apocalyptic Saiyuki world, their bond might be tested in new ways. Fanfics could also focus on how they grow together, like Goku learning more about his powers from Konzen, or Konzen becoming more empathetic because of Goku.
One idea could be that Goku and Goku Black are forced to team up against an even greater threat from another universe. They start to understand each other's fighting styles during the battle and gradually develop a grudging respect for one another.
A well - known 'sanzo x goku fanfic' is 'In Each Other's Shadow'. This fanfic is great as it shows the contrast between their personalities and how they complement each other. Sanzo's more serious and guarded nature against Goku's carefree and innocent self creates an interesting dynamic. Additionally, some fanfics might explore how they face challenges together that test their relationship, like in 'Trial of Trust'.
Maybe the goddess has a prophecy about Goku being the key to saving her realm from an ancient evil. So she forms a bond with Goku, and as they get to know each other better, Goku starts to develop feelings for her. Their relationship then becomes a driving force for him to fulfill the prophecy and defeat the evil, all while exploring the unique aspects of their two different worlds.
In a fanfiction, there could be a scenario where an ancient prophecy foretells of a combined power of Trunks and Goku being the only thing that can stop an impending doom. They start training together to master a special fusion technique that no one has ever attempted before. Along the way, they face challenges not only in their training but also in dealing with their own egos and differences in fighting styles.
A really interesting plot could be set in an alternate universe where Goku and Launch are arranged to be married for some political reason in the Saiyan or Earthling world. They start off not really liking each other but as they face challenges together, they fall in love. For example, they have to deal with a group that is against their union and in the process, they learn about each other's strengths and weaknesses.
Perhaps in a different universe, Turles and Goku are brothers. They grow up together, training side by side, but then a prophecy divides them as they are told one must defeat the other for the greater good. This creates a complex relationship full of love, rivalry, and moral dilemmas.
Well, a Saiyuki crossover fanfiction could involve crossing it with a post - apocalyptic world. The Saiyuki gang would have to adapt to the harsh new environment, deal with new threats like mutated creatures and fight for survival. Or perhaps a crossover with a space - opera setting. They could travel among the stars, encounter alien species and get involved in intergalactic politics.
One idea could be that the OC is from a different dimension and has a unique power that Goku Black is intrigued by. He decides to use the OC to further his own evil plans at first, but then starts to develop unexpected feelings. Another plot could be the OC being a time traveler who tries to stop Goku Black's rampage, but gets caught in his web of lies and manipulation. A third option is the OC is a Saiyan hybrid who is initially on Goku Black's side because she is misled by his false charm, and then has to face the truth and make a difficult choice.