Charlie is a really interesting character to focus on. His charm and his schemes often drive the story forward in the original, and in fan fiction, you could explore his thoughts and motives even more. Maybe you could write about his dreams that are hidden beneath his con - artist exterior.
One possible plot idea could be exploring the backstories of the characters in more depth. Maybe delving into their childhoods and how those experiences shaped them into the people we see in the original work. For example, we could learn about their family dynamics and how it influenced their actions and decisions in the story.
Definitely Licanius himself. His complex personality and the decisions he makes throughout the trilogy offer a lot of room for exploration in fan fiction. Another interesting character is the antagonist. You can dig deeper into their motives and maybe give them a more sympathetic backstory. And then there's the wizard character, who has a lot of mysterious powers that could be further developed in fan - made stories.
Rey is an obvious choice. Her journey from a scavenger to a powerful Jedi is full of potential for further exploration. You could write about her internal struggles with her newfound power and her place in the galaxy. Finn is also interesting. His growth from a stormtrooper to a Resistance hero can be delved into deeper. For example, his experiences in the First Order and how they still affect him during the fight against Palpatine.
The servants in the castle are really interesting characters in Beauty and the Beast fan fiction. Lumiere and Cogsworth, for example, have such distinct personalities. Lumiere is flamboyant and romantic, while Cogsworth is more uptight. Fan fiction could explore their lives before the curse, how they became the way they are, and their hopes for the future. Also, Mrs. Potts with her motherly nature can be a central character in stories that focus on the family - like atmosphere within the castle.
The main character is always a good start. Their internal struggles and growth throughout the story can be further explored. Also, any mysterious characters that were only briefly mentioned in the original could be very interesting. For example, that strange old man who seemed to know more than he let on.
Randall is a very popular choice. His complex backstory, his struggle with identity, and his strong family values make him an interesting character to explore further in fan fiction.
John Nolan is often a popular choice. He has a lot of growth throughout the show, and his unique position as an older rookie makes for interesting storylines.
Villains can also be very popular. There's a lot of potential in delving deeper into their motives. Maybe in the fan fiction, you can show a different side of the villain, like a tragic backstory that led them to become evil. This can make the character more complex and interesting.
Kristy is often a popular choice. She's the founder of the Babysitters Club, so there are a lot of possibilities for stories centered around her leadership skills and how she started the club. Claudia is also very popular. Her unique style and love for art can be a great focus. And Mary Anne, with her shy and sweet personality, can be the main character in stories about friendship and personal growth within the club.
Klaus is a very popular character to focus on. His ability to communicate with the dead gives a lot of room for creative and spooky storylines. Writers can explore his relationship with the spirits and how it affects his life among the living.