Some fanfictions also pair Lucy with Caspian. Lucy has her own unique magic and kindness, and when paired with Caspian, it can create interesting relationships, like her helping Caspian understand the more magical aspects of Narnia.
One idea could be a story where Peter and Caspian have to go on a secret mission together to find a lost magical artifact that can save Narnia from a new threat. They start off not getting along but gradually learn to respect each other's skills.
The White Witch could make a great antagonist even in a Prince Caspian and Peter fanfiction. Her evil magic and desire for power are well - known. She could return in some form, perhaps a remnant of her magic that was left behind and has now taken on a new, more insidious form. Another option could be a power - hungry Narnian noble who wants to overthrow Prince Caspian and sees Peter as a threat to his plans. He could be sly and manipulative, causing trouble for both of them.
One idea could be that Peter gets lost in the forest of Narnia on his own during a quest and has to rely on his wits and some unexpected help from a minor character in the Prince Caspian story to find his way back to the main group. Another could be a time - travel twist where Peter is sent back to a crucial moment in Prince Caspian's past and has to figure out how to change things without disrupting the future of Narnia too much. And perhaps a story where Peter and Prince Caspian have a misunderstanding that leads to a mini - adventure to resolve their differences and strengthen their bond.
There's also 'Lucy's Secret Journeys'. In this fanfiction, Lucy discovers a hidden power within herself and Peter has to help her control it. It's full of emotional moments and great character development. The author does a wonderful job of staying true to the original characters while adding new twists.
Perhaps Peter's job in the bar is a way for him to gather information. He might be on a secret mission, and the bar is a place where all kinds of characters come. He has to blend in as a bartender while listening for any useful news. He could meet old Narnian friends or foes in disguise there.
The theme of redemption can also be found. Sometimes an original character has made mistakes in the past and through their interactions with Peter, they seek redemption. Additionally, the theme of family is there. Even though the original characters are new, they often become part of Peter's 'family' in Narnia, and they learn the importance of family bonds and loyalty.
Websites like Archive of Our Own (AO3) are great places to start. It has a large collection of fanfiction, and you can easily search for 'Harry Potter' and 'Peter Pevensie' crossovers. There are filters to help you find the most popular or recently updated ones.
One great 'Harry Potter' and 'Peter Pevensie' fanfiction is 'The Unlikely Alliance'. It combines the magic of Hogwarts with the Narnian world in a really interesting way. The characters from both universes interact in a believable manner, like Harry and Peter teaming up to fight a common enemy that threatens both their worlds.
Some fanfictions focus on the relationship between Peter and Caspian when they first meet. It could explore how they initially view each other with suspicion, being from different worlds in a way. But as they start to understand each other's motives and the importance of their roles in Narnia, they form a strong bond that helps them protect Narnia from various threats.