Another theme is the exploration of their differences. Felix is bold and fearless while Bernadetta is timid. Fanfictions often play with how these differences attract them to each other. They start to understand and complement each other's traits.
One popular Felix x Bernadetta fanfiction is 'A Chance Encounter'. It beautifully depicts their relationship development from initial awkwardness to deep understanding. The author does a great job of showing Felix's stoicism and Bernadetta's shyness.
Friendship is another theme. They start as acquaintances or teacher - student in the game context, and in fanfics, their friendship blossoms. It could be through shared hobbies like reading or gardening, which is often explored in the fanfics.
Well, 'Bernadetta and the Mysterious Garden' is a fanfic that really stands out. It takes her love for solitude and her creativity and builds a whole new story around it. There are also some fanfics that focus on her relationships with other characters in the game, like 'Bernadetta and Ferdinand: An Unexpected Bond' which explores their dynamic in a unique way.
There's a fanfic titled 'A New Chapter for Byleth and Bernadetta' which is quite interesting. In this fic, Byleth helps Bernadetta come out of her shell in a very natural way. The author does a wonderful job of portraying their interactions and how they grow closer over time.
First, study Bernadetta's character traits. Notice her shyness, her love for writing, and her tendency to isolate herself. Then, come up with a unique plot that can involve these traits. For example, you could write about her going on a quest to find a rare book for her writing inspiration.
Max Schreiber is quite interesting. He's a wizard with his own motives and powers that often play into the adventures of Gotrek and Felix. His magical abilities add an extra layer of complexity to the story.
I'm not sure specifically what 'felix fanfic' is about without more context. It could be a fanfic related to a character named Felix. Maybe it's about Felix's adventures, relationships, or his role in a particular fictional world.