Well, if Goku could see the future in fanfic, it might give him a huge advantage in battles. He could strategize better and protect his friends and the Earth more effectively. But it could also make things a bit too easy for him and take away some of the excitement and challenges.
It could lead to some really interesting plot twists. Maybe Goku could prevent major disasters before they happen and change the course of events in the Dragon Ball universe.
In a fanfiction where Kid Goku meets Future Goku, one possibility is that Future Goku would be amazed at seeing his younger self. He might share some of the dark experiences he has had in the future, like the battles against powerful enemies and the losses. Kid Goku, being young and full of energy, could be inspired by Future Goku's strength and determination. Maybe he would start training even harder, eager to reach the level of his future self.
In the fanfiction, perhaps they team up to fight a common enemy. Goku's raw power combined with Gohan's strategic mind from the future battles could make them an unbeatable duo. They'd exchange blows and strategies, and their teamwork would be amazing to read about.
In a Konoha 12 see the future fanfiction, many things could occur. They might see the destruction of Konoha and strive to prevent it. For example, Naruto could use his future knowledge to better train and unite the village. Sakura might focus on advancing her medical skills even further to deal with future threats. And Sasuke could use the knowledge to avoid certain paths that led to his past miseries.
Well, they might see a future where they have a big family. Since Naruto always wanted to be acknowledged and have people around him, he could see himself surrounded by his children and Hinata in a happy home. And for Hinata, she might see herself as a strong kunoichi, still supporting Naruto in his Hokage duties.
In this fanfiction, perhaps Hinata sees a future full of danger for Konoha. She then has to figure out a way to prevent it, with Naruto by her side. It could be that they face new and powerful enemies that they've never encountered before. She might see different possible outcomes depending on the actions they take in the present.
One possible plot could be that they see a future where the wizarding world is in great danger again. So they start to train young wizards secretly to prepare for the upcoming threat.
If Naruto sees a future where he and Sakura are not as close as they are in the present, he might start to distance himself from her, thinking it's for the best. Or on the other hand, he could try to change the future by being more open and communicative with her. Also, with Sasuke, if he sees a future where Sasuke is in more danger than he thought, he would redouble his efforts to keep Sasuke safe and this would likely deepen their complex relationship.
In a fanfiction where Future Gohan meets Goku, it could be an emotional reunion. Gohan might be filled with a sense of relief and joy, seeing his father again. He could show Goku all the things he's been through in the future, and Goku would be both proud and sad about what his son has endured.
If they saw the future, perhaps Naruto would see himself failing to save Sasuke. This could make him change his approach towards Sasuke, trying to understand his friend's pain more deeply and find a better way to bring him back to the right path. They might also foresee new and powerful enemies emerging, and start to search for allies or new jutsu to counter them.
The plot could involve Goku and Goku Black fusing accidentally. Maybe due to some strange energy anomaly. And then they have to figure out how to control this new form. They might initially be feared by their friends because of Goku Black's reputation, but then they prove that they are on the side of good by using their new powers to protect the Earth from an impending threat that no one else could handle.