James is likely portrayed as brave and heroic. He is willing to put himself in danger to save Lily, showing his chivalrous side. He probably also has a bit of a cocky streak as he is confident in his ability to rescue her.
In some versions, James might use his Quidditch skills to create a distraction while rescuing Lily from a dangerous situation Snape unknowingly led her into. For example, he could fly in on his broomstick and snatch her away just as a spell was about to hit her.
In this type of fanfiction, a plot twist could be that Snape saves them, but they end up having to go into hiding in a completely unexpected place. Maybe they have to live among muggles in a way they never thought possible. Another plot twist could be that Snape saves them, but then realizes that he has put himself in a very dangerous position with Voldemort's followers. So he has to find a way to protect himself while also protecting Lily and James. And there could also be a plot twist where Snape saves them, but they don't believe his motives are pure and they try to escape from him, leading to a whole new set of adventures and challenges.
In many fanfictions, Snape's jealousy of James and Lily can be deeply rooted in his unrequited love for Lily. Snape had a complex relationship with Lily from their childhood. He loved her deeply, but she fell in love with James. This led to his intense jealousy. His envy towards James was not just about Lily's love, but also about James' popularity and charm which Snape felt he lacked.
Love and jealousy are very common themes. Snape's unrequited love for Lily while she is with James creates a lot of jealousy. It often drives the plot as Snape's actions are influenced by his feelings.
Unrequited love is a very common theme. Snape's love for Lily that was never fully reciprocated is often explored in depth. It adds a lot of emotional depth to the stories.
Guilt and redemption can be a theme too. Snape's actions were often driven by his love for Lily and his guilt over her death. Fanfictions may expand on this, showing how he tries to make up for it in different ways. Also, the theme of loyalty - Snape's loyalty to Lily even after her death is a powerful concept that fanfictions often explore, sometimes by creating scenarios where Lily somehow comes back or is still present in a way that tests Snape's loyalty.
One possibility is that Snape has a change of heart. Maybe he realizes that despite their differences, James is a father and a valuable member of the wizarding world. In some fanfictions, Snape might be in a situation where he sees James being wrongly accused, and his sense of justice kicks in to save him.
Snape's view of James might not change much at first. He has such deep - seated hatred for James due to their past. But if the fanfiction shows James in a more positive or sympathetic light, he may start to question his long - held beliefs about him, just a little bit.
There's a fanfic called 'Snape's Hidden Heroism for Lily'. In this story, Snape discovers a plot against Lily early on and starts devising ways to keep her out of harm's way. He sacrifices his position among the Death Eaters and risks his own life in the process. Another interesting one is 'When Snape Saved Lily'. It details a scenario where Snape has to fight his former friends to rescue Lily from a deadly trap.