One interesting plot could be the Winter Soldier traveling back in time to prevent his own transformation. He could meet his pre - Hydra self and try to change the course of events that led to his brainwashing. Another plot might involve him traveling to different historical events and using his skills to alter the outcome in ways that benefit the future. For example, he could go back to World War II and help the Allies in a more covert way, using his super - soldier abilities.
Another plot could involve the Winter Soldier being given a pet as part of a rehabilitation experiment. Maybe it's a cat that is initially very skittish around him, but over time they develop a bond. The pet could also be a target of the bad guys, which would lead to the Winter Soldier having to protect it and in the process, further break free from his programming.
The Winter Soldier's character development through time travel is complex. He might travel back to a time when he was still Bucky Barnes, before all the trauma. This encounter with his former self could stir up memories and emotions that he had long buried. As he moves through different times, he could learn new values and ways of thinking. For example, in a more technologically advanced future, he could learn about new forms of therapy that help him deal with his past. Time travel also gives him the opportunity to see how the world has changed because of his actions, both good and bad, which can shape his future self.
One interesting plot could be a character going back in time to prevent a certain card from being created, which then changes the whole Yu - Gi - Oh! tournament scene. For example, if the Blue - Eyes White Dragon card was never created, how would the power balance shift among duelists?
One interesting plot could be Superman traveling back in time to prevent the destruction of Krypton. He could use his powers to stop the cataclysmic events that led to its downfall. Maybe he tries to convince the Kryptonian council of the impending danger, but faces resistance as they don't believe him at first.
Another plot could be that they travel to a future time where music has evolved into something completely different. They struggle to understand the new forms of music but also bring back some of the old charm from their time, creating a unique blend that revolutionizes the future music scene.
Another plot might be Kratos traveling to a time in the future of his own world. He could see the consequences of his actions and how the world has changed. Maybe he discovers that his actions have led to a new threat emerging, and he has to figure out how to fix it. This would add a new layer of responsibility to his character.
Well, in some time travel Kakashi fanfictions, there's a plot where Kakashi goes back in time right after Obito's 'death'. He tries to save Obito in a different way, not just by taking his eye. He could change the whole course of events that led to the formation of Akatsuki and the many tragedies that followed. This would completely rewrite the story of Naruto in many ways.
One interesting plot could be Octavia traveling back in time to prevent the initial war on Earth. She might use her knowledge of future events to broker peace between the different factions. Another could be her traveling to the time before the Ark was built to see if there were other ways to solve the overpopulation problem without having to send people to the ground in such a dangerous way. And she could also time travel to a future version of the world to see what kind of society has been built after all the chaos on Earth in her original time.
In some pokemon time travel fanfiction, the main character travels to the future. There, they might find that Pokemon have evolved in unexpected ways, like having new types or abilities. They then have to adapt and figure out how to battle with these new forms of Pokemon.
One interesting plot could be a modern person traveling back to WW2 and using their knowledge of future technology to help the Allies in a covert way, like improving communication systems. Another could be a time traveler trying to prevent a particular tragic event during the war, such as the bombing of a certain city. And there might be a plot where the time traveler has to adapt to the harsh wartime conditions and forms unexpected friendships with soldiers on the front line.