Another interesting plot would be if Jon Snow went back to the time when his father, Ned Stark, was a young man. He could interact with his father, perhaps change some small events that had big consequences later. He might also learn more about his family's secrets directly from Ned, things that were lost in time in the original story.
Jon Snow could be sent back to a time just before Ned Stark's father was killed. With his future - learned wisdom, he could try to save his grandfather and thus change the entire Stark family's fate. He may also discover secrets about his own lineage that were lost in time. This could lead to him having more power and influence in the past, as he might be able to claim certain rights or titles based on this new - found knowledge.
One idea could be that Team 7 goes back to the time of the founding of their village. They could meet the original founders and learn about the true origins of their ninja way. Another could be that they go back to a time when a great war was about to start and they use their future knowledge to try and prevent it. Or perhaps they go back to a time when a powerful and evil ninja was first emerging and they work to stop his rise to power.
One idea could be that Ron goes back in time and accidentally changes a major event at Hogwarts, like preventing the formation of the Marauders. So then all the events related to them in the original timeline, like the creation of the Marauder's Map, are affected. This would lead to a whole new set of adventures for Ron as he tries to fix what he has broken.
A great plot idea is Loki going back to the very beginning of the creation of the Nine Realms. He might discover some long - lost secrets about the origin of power in the universe. Maybe he could find a way to harness this ancient power and use it to change his own fate and the fate of Asgard. Another idea is that he travels back to a time when he first met the Avengers. He could try to form different relationships with them, either befriending them earlier or finding a way to outwit them in a more clever way, which would completely change the events of the movies.
Another plot could involve Jon Snow's werewolf nature being related to his true parentage. What if his Stark and Targaryen blood combined in a way that made him a werewolf? This could lead to a whole new take on his destiny and role in the power struggles of Westeros.
One plot idea could be Kagome accidentally traveling to the world of 'Game of Thrones' during a time when Jon Snow is in a great struggle. She could use her spiritual powers from her own world to help him sense approaching danger, like the White Walkers. For example, she might be able to detect their movements in a way that no one in Westeros can.
One plot idea could be that Link goes back in time and has to prevent a major disaster that was previously thought to be inevitable. For example, he could stop the Calamity Ganon from ever being released in the first place by changing certain events in the past. Another idea is that he goes back and meets his ancestors, learning new skills and knowledge from them that he can bring back to his own time to better fight against the evils in Hyrule. Maybe he also discovers a long - lost prophecy that only makes sense in the context of his time - traveling adventure.
One plot idea could be that Bilbo goes back in time to the founding of the Shire. He could use his knowledge from his own time to help shape the early laws and traditions in a more positive way. For example, he might introduce better farming techniques he learned from his travels, which could lead to the Shire being even more prosperous in the long run.
One plot idea could be Harry going back to the time when Voldemort was still at Hogwarts as Tom Riddle. He could try to prevent Riddle from turning into Voldemort by befriending him and showing him a different path. Another idea is that Harry goes back to the time of the founders of Hogwarts. He might learn ancient magic directly from them and use that knowledge to change the future of the wizarding world. Also, he could go back to a time when his parents were alive and get to know them better, which would be a very emotional journey for him.
One idea could be that they go back to the time when their parents first met. They could try to prevent some dark force from interfering with their relationship, which would change the course of their family's future. Another plot could be them going back to a crucial moment in the fight against a major demon, and they use their present - day knowledge to change the outcome for the better.