Neville Longbottom could be really interesting. He's usually so shy and awkward, but at the Yule Ball, he could have a moment of confidence. Maybe he asks a girl who no one expected him to ask, or he could show off some hidden dancing skills. Another option is Luna Lovegood. She might wear a really unique and eccentric dress to the ball, and her strange but endearing personality could make for some great interactions during the event.
I think Professor Flitwick could be an interesting choice. He is small in stature but big in magic. He could use his charm and levitation spells to create some unique dance effects. For example, he could make the students levitate slightly while dancing to give an ethereal look. His knowledge of charms could also be used to add some fun elements to the dance class, like making the dance floor sparkle or creating musical accompaniment with magic.
There's also a possibility that it's a new character created specifically for this fanfiction. This new character could bring a fresh perspective and allow the author to explore different aspects of Harry's gentlemanly behavior at the Yule Ball.
One interesting storyline could be about a character who was initially too shy to ask someone to the Yule Ball but finally gathers the courage at the last minute. Maybe a Hufflepuff student who has a crush on a Ravenclaw but is afraid of rejection. They spend the weeks leading up to the ball trying to find ways to talk to the Ravenclaw and in the end, they have a magical night at the ball.
In some fanfictions, the Yule Ball is a turning point for Harry and Daphne's relationship. For example, Daphne might be a bit of an outcast in her own Slytherin house for being different. When she goes to the ball with Harry, they face a lot of stares. But they don't let it bother them and instead have a great time, chatting about magic, Hogwarts secrets, and their dreams for the future. This could be the start of a beautiful friendship or something more.
Perhaps there are some misunderstandings at the start. Fleur might think Harry is just another typical Hogwarts boy, but as the ball progresses, she sees his courage when he stands up to a bully or helps someone in need. Harry, on the other hand, realizes that Fleur is not just a beautiful face but also a strong and intelligent witch. This realization on both sides could lead to a more meaningful relationship development.
Kira from The Dark Crystal could also be an interesting focus. If she were in the Harry Potter universe, her natural connection to nature and her strong will could make her a formidable ally. She could teach the Hogwarts students about the importance of nature in magic, which is something that is often overlooked in the wizarding world. Her skills with animals could also come in handy, like when dealing with magical creatures at Hogwarts.
Doctor Strange would be an interesting character to focus on in a Harry Potter MCU fanfiction. He already has knowledge of magic in the MCU, but it's a different kind of magic compared to that in Harry Potter. He could compare and contrast the two magics, and perhaps even learn new spells from the Harry Potter universe. His presence could also bridge the gap between the two universes in terms of magic.
Well, a plot could involve a character who is an outcast getting a magical makeover just for the Yule Ball. They enter the ballroom and everyone is shocked. Or perhaps there's a mystery at the Yule Ball. A valuable magical item goes missing during the event, and the main characters have to solve the mystery before the night ends. It could also be about two rivals who end up having to dance together at the Yule Ball and discover they have more in common than they thought.
One possible fanfiction could be that Susan Bones, being a bit shy, is initially hesitant to go to the Yule Ball. But when Harry Potter asks her, she's overjoyed. At the ball, they share a slow dance, and Harry realizes how kind - hearted and intelligent Susan is. They end up spending the whole night chatting and dancing, forming a new friendship that might develop into something more in the future.
There's 'The Yule Ball Encounter' which is a short but sweet fanfiction. It focuses on the moment when Harry and Daphne first see each other at the ball. The author does a great job of capturing their initial reactions and the tension between them. It's a quick read but very engaging.