There are some fanfictions where the time travel is not just about changing the past, but also about learning from it. For instance, Luke travels back to the time of his father's youth. Instead of trying to directly change Anakin's path, he tries to understand the root causes of his fall. He then takes this knowledge back to his own time to better prepare the Jedi order for future threats. And Leia, when she travels back, might focus on building alliances that could have prevented the rise of the Sith in the first place. This kind of plot adds depth to the characters and the overall Star Wars universe.
One idea could be that Luke and Leia time travel back to the time before their parents' relationship soured. They could try to prevent Anakin's fall to the dark side, which would in turn change the fate of their family. Their presence might also have unforeseen consequences, like disrupting the natural flow of the Force. Maybe they meet their younger selves as children, which would create some really interesting and complex scenarios.
I really liked 'The Time - Traveling Skywalkers'. It's a story where all four characters are caught in a time - travel anomaly. They end up in different points in time relative to each other. Padme gets to see a future where her children have grown up strong despite all the hardships. Anakin has to face his past self and tries to guide him away from the dark side. Luke and Leia use their knowledge of the future to try and make the galaxy a better place in the past. It's a really engaging read.
One possible plot could be that Anakin, Padme, Luke and Leia are sent back in time to the Clone Wars era. Anakin could have the chance to prevent his fall to the dark side, with Padme by his side to support him. Luke and Leia would be there to help their father, using the knowledge they have from the future. They could change the course of the war and save many lives, while also ensuring the Sith don't gain so much power.
Maybe in the fanfic, Padme discovers a time - travel device and decides to use it to go back in time to when Anakin was still a young Jedi. She hopes to change the course of his life and prevent his turn to the dark side. Luke and Leia, sensing something is wrong with the timeline, follow her. Once there, they have to navigate the complex politics and relationships of that era while also trying to keep their true identities a secret. This could lead to all sorts of interesting interactions and plot twists.
In a time - travel scenario, Anakin and Luke's relationship could be transformed. Luke could finally understand his father's struggles more intimately by being present in the past. Padme and Leia might form a stronger bond as well, with Padme being able to mentor Leia in ways she couldn't before. Their relationships would be shaped by the new shared experiences in different time periods and the knowledge they gain from those travels.
In this kind of fanfic, a lot could happen. Maybe Anakin could use time travel to prevent his fall to the dark side. He might go back and make different choices, which would then change the entire future for Luke and Leia. Padme could also be involved in this time - traveling adventure. For example, she could use her knowledge of future events to try and save the Republic in a more effective way. And Luke and Leia, they might end up traveling through time as well to learn more about their parents' past and the history of the Jedi and Sith.
If Anakin and Padme time travel, it could change the circumstances of their children's birth. For example, if they prevent certain events, Luke and Leia might not be born at all. Or, if they change things in a positive way, their children could be born with even greater Force potential. Maybe they could be born in a time of peace and grow up without the threat of the Empire.
One great storyline could be a 'what if' scenario where Anakin doesn't turn to the Dark Side. In this, he and Padme raise Luke and Leia together. The twins grow up with their father's Jedi training and the family lives in harmony, facing the challenges of the galaxy as a united front.
One idea could be a time - travel plot where Luke and Leia are sent back in time and meet their parents, Anakin and Padme, before Anakin's fall to the dark side. They try to prevent the events that led to the rise of the Empire.
Here's another idea. Suppose there's a threat to the galaxy that can only be stopped by using a long - lost technique that Padme knew about. Luke and Leia, with the help of Anakin's spirit, embark on a quest to find out about this technique. They face many challenges, including political intrigue and dark side threats, all while coming to terms with their family's complex history.