Another theme is power. She may use her knowledge of the future to gain power or influence in the past. This could be political power, like influencing the decisions of the lords, or personal power, such as learning combat skills earlier. It's about how she can rewrite her own story with the advantage of hindsight.
One of the most common characters is definitely her father, Ned Stark. Since Sansa has the chance to go back in time, she would likely interact with him a great deal to try and change the course of events. Another is Arya. They could team up and use their combined knowledge and skills to make a difference. And of course, Littlefinger. Sansa would be more aware of his manipulations this time around and might interact with him in a more strategic way to outwit him.
In this type of fanfiction, a great plotline could be Sansa influencing the political landscape much earlier. She could use her knowledge of how certain houses would act in the future to her advantage. For example, she could form early alliances with houses that she knows will be important later. She might also try to change the way her family views certain people. Maybe she could convince her father to see Littlefinger's true nature much sooner. This would not only protect her family but also change the entire power dynamic in Westeros.
One great Sansa back in time fanfiction is 'Sansa's Time - Travel Adventure'. It has Sansa going back to key moments in her family's history and trying to change things for the better. The story is really engaging as it shows Sansa using her wits and new - found knowledge from the future.
Sansa would be more assertive in her political moves. She has seen the consequences of inaction and bad decisions in the future. So, she would be quicker to make decisions that benefit her family and herself. For example, she might be more involved in military strategies to protect the North.
One idea could be that Sansa goes back in time and tries to prevent the Red Wedding. She could use her knowledge of the future to warn her family and change the course of that tragic event.
Time travel can make Sansa more confident. When she travels back, she has the knowledge of future events. So she can be more assertive. For example, she won't be as easily manipulated as she was before. She becomes a stronger character as she tries to change the fate of her family.
Another theme is self - discovery. By traveling through time, Sansa gets to see different versions of herself and learn more about her own strength and capabilities. She might realize she was stronger than she thought in the past or find new skills in different time periods.
She would become more confident earlier. Instead of being a naive girl in King's Landing, she'd use her time - travel knowledge to be assertive. For example, she'd not be easily manipulated by Cersei.
A common plot is that Jon and Sansa travel back in time to change the events that led to the downfall of their family. They use their knowledge of the future to try and prevent tragedies. For example, they might stop Ned Stark's execution. Another popular plot is that they travel to a different time period in Westeros' history and get involved in the events there, like during the time of Aegon the Conqueror.