One interesting scenario could be a rewrite of their relationship where Joffrey is secretly influenced by a more benevolent force. This might lead him to treat Sansa with more kindness than in the original series. Maybe he starts to see the value in having an ally in Sansa rather than just using her as a pawn.
Another scenario could be a time - travel fanfiction. Sansa somehow goes back in time and decides to try and change her relationship with Joffrey from the start. She could use her knowledge of his cruel nature to avoid the worst of his actions towards her and perhaps even try to reform him.
One interesting scenario could be that it was actually a planned assassination by a secret alliance of the Starks and the Tyrells long before the wedding. They worked together in the shadows, using Sansa as an unwitting pawn. The Tyrells provided the poison, and the Starks had someone in place at the wedding to ensure Joffrey drank it.
One interesting scenario could be Sansa and the Hound meeting again after a long time apart. Sansa has grown stronger and more self - assured, and the Hound is still his gruff self. They might have a conversation where Sansa stands up to him in a new way, showing how much she has changed since they last interacted.
Another scenario could be a more romantic one. Theon, having redeemed himself, realizes his true feelings for Sansa. They might have a moment where they share their past traumas and find solace in each other, slowly building a relationship based on mutual understanding and respect.
In many fanfictions, secondary characters around Sansa and Joffrey are well - written. For instance, Tyrion. His relationship with both Sansa and Joffrey in the original series was complex. In fanfiction, his character can be used to further the plot involving Sansa and Joffrey. He might be the voice of reason or a catalyst for change in their relationship.
Some fanfictions might focus on an alternate universe where Joffrey is not a king. He could be a simple knight, and the story could explore how his personality would develop without the power and privilege of the throne. He might learn humility and honor in a different way.
Another plotline might involve Ramsay having a change of heart due to some unexpected event. For example, he could be haunted by his past deeds and start to treat Sansa differently. However, this would be a very complex and controversial change as he is such a cruel character. In this scenario, Sansa would have to decide whether to trust this new side of Ramsay or still seek her revenge.
One interesting storyline could be Sansa and Theon teaming up to take revenge on their common enemies. They've both been through so much in the original series, and in fanfiction, they might use their combined knowledge and skills to outwit those who wronged them.
One interesting plotline could be Sansa gradually seeing through Littlefinger's manipulations. She starts to notice the subtle ways he tries to control her and uses her new - found political acumen to outwit him. For example, she might pretend to still be under his thumb while secretly gathering allies against him.
One interesting storyline could be Jon and Sansa ruling Winterfell together in a more harmonious way than in the show. They could face challenges from the remaining enemies in the North and strengthen their bond through mutual respect and strategic planning.
One interesting plotline could be Sansa and Tyrion forming an unexpected alliance to outwit their enemies in King's Landing. They both have been used as pawns in the political games, and together they could use their wits and knowledge of the court to gain an upper hand.