Perhaps he travels back in time and accidentally changes something that has a huge ripple effect on his present. For example, he might prevent himself from ever becoming a Ravager. This would lead to a whole new set of adventures as he tries to fix the timeline while also dealing with the consequences of his changed past, like not having the relationships or skills he had in his original timeline.
Another exciting plot could involve Peter Quill traveling to different points in time to collect powerful artifacts. Maybe he discovers that these artifacts, when combined in a certain way, can give him the power to defeat a great evil in his own time. Along the way, he meets different versions of his friends and enemies from various timelines.
The main antagonist could be a time - traveling version of Ronan the Accuser. He could be from a timeline where he wasn't defeated and has now set his sights on destroying not just Xandar but all of the galaxy across different timelines. Peter Quill would have to use his time - traveling abilities to stop him before he becomes too powerful.
One popular theme is his search for family. Since he lost his mother at a young age and was abducted from Earth, many fanfictions explore his longing for a family and how he creates new bonds. Another is his adventures across the galaxy, like exploring new planets and encountering strange species.
One possible plotline could be Grogu traveling back to the time of the Jedi Order's prime. He could meet the great Jedi Masters and learn from them directly. This would be amazing as he could gain more knowledge and skills, and it might also change the course of his own future.
One exciting plot could be that Teddy and Lily travel back to the time of dinosaurs. They have to survive in a world full of giant reptiles and strange plants. They might discover new species that were not known before and their knowledge about dinosaurs could help modern science when they return to their own time.
One possible plot could be that Peter Parker, while on a school trip or some scientific research in space (maybe with Stark tech), accidentally stumbles upon Peter Quill and the Guardians of the Galaxy. They initially have a bit of a misunderstanding as their ways of doing things are quite different. Parker is used to the more down - to - earth (literally) problems in New York, while Quill is dealing with intergalactic threats. But they soon realize they can learn from each other. Parker could teach Quill about the latest Earth - based technology, and Quill could show Parker the wonders of the galaxy.
One common theme is power amplification. Writers often explore how Peter Quill could become even more powerful, like getting new abilities related to his Celestial heritage.
Well, in a Naruto time travel future fanfiction, a plotline could be Naruto finding himself in a future where the chakra system has been completely disrupted. People are suffering because of this. He uses his time - traveling knowledge to find a way to fix it. Another idea is that he travels to a future where the five great nations are at war again, but this time it's a more technological and brutal war. He has to use his experience and charisma to stop the war and bring peace once more.
A really interesting plot twist could be that in the time - travel, Luffy and Zoro switch bodies. This would lead to a lot of comical situations as they try to adapt to each other's abilities. Zoro in Luffy's body would have to deal with the stretchy powers, and Luffy in Zoro's body would have to handle the three - sword style. It would also create some unique battle strategies as they fight enemies.
One possible plot twist could be Goku traveling back in time to the Saiyan - Planet Vegeta era. He could try to prevent Frieza from destroying the Saiyans. This would completely change the course of the Dragon Ball story as we know it, with a much larger Saiyan population and different power dynamics.
The child in fanfiction could potentially have some sort of special power. Maybe it could inherit Peter's ability to hold an Infinity Stone (if we consider that as a latent power) and Gamora's enhanced physical abilities. It would be raised in a universe full of danger and wonder. It could befriend the other Guardians and learn from them. This child might also struggle with the legacy of its parents, having to live up to their great reputations while also carving out its own path in the galaxy.