Another possibility is that Captain America goes back in time to retrieve something important. Maybe it's a lost artifact or some crucial information. Along the way, he would have to navigate the past world, deal with the people and situations of that time, and also avoid changing too much of the timeline to prevent unforeseen consequences.
In this fanfiction, he could also meet his past self. It would be an interesting encounter. They might have a conversation about his future experiences and how to better protect the world. And he may use his knowledge of the future to train his past self, making him an even better hero.
He could meet Peggy Carter. Since he had a strong connection with her in the past, it would be a very emotional reunion. They might share some unspoken feelings that were left unexpressed before.
He could change the course of major events. For example, he might prevent the rise of a powerful villain. This would have a huge impact on the entire galaxy. Maybe he could save some characters who died in the original timeline.
In this fanfiction, Sora might change key events. Maybe he could prevent some of the tragedies that occurred in the original story. For example, he could save a character who was lost before.
She might change important events in the wizarding world. For example, she could prevent certain dark magic incidents or save characters who died in the original timeline.
Well, he might meet his ancestors. It could be really interesting to see how they interact and what kind of influence he has on their lives. Maybe he'll change some small events that end up having a big impact on his present time.
In this kind of fanfiction, Jotaro might change some crucial events. For example, he could prevent some of his friends from getting hurt or even stop the main villain from starting their evil plans at an earlier stage. This would completely change the original story's timeline and create a whole new set of adventures and challenges for Jotaro and the other characters.
Well, he might prevent some of the villains from ever becoming powerful. For example, he could stop Frieza from getting all those power - ups.
Well, she might meet historical figures. For example, she could encounter Cleopatra and have an interesting conversation about ancient Egyptian politics and culture.
In the 'Petunia Goes Back in Time' fanfiction, she might try to change things that happened in the past. Maybe she wants to fix a mistake or prevent a bad event from occurring.
One possibility is that Draco could try to change his family's fate. In the original story, his family was on the wrong side of the wizarding war. By going back in time, he might attempt to steer them towards a more positive path, perhaps by preventing them from getting involved with Voldemort in the first place.