Well, Harry Potter himself is likely to be one of the main characters. He might have a new or different familiar in the fanfiction, and his relationship with it could be a central part of the story. Hermione could also be a main character, perhaps using her intelligence to study and understand more about familiars.
Definitely owls. In fanfiction, they can be much more than just messengers. They might be able to understand complex spells and help their owners study magic. Another popular one is the toad. Some fanfictions give toads the ability to predict the future in a small way. And cats, of course. Cats in fanfiction can be very mysterious and have powers like seeing through invisibility cloaks or sensing when a Death Eater is nearby.
One interesting plotline could be the discovery of new and rare familiars. For example, a character might find a phoenix-like familiar with unique powers that helps them in their adventures. Another could be familiars from different magical cultures coming together, like a Japanese Kitsune and a European Griffin working as a team.
A Thestral could also be a familiar for Harry. Since he can see Thestrals, it makes sense in the context of fanfiction. Thestrals could provide a unique form of transportation for Harry and also have some special abilities related to the afterlife or death magic that could be explored in the story.
In Harry Potter fanfiction, some common familiars include owls like Hedwig, which are often depicted with special abilities or personalities. There are also cats, such as Crookshanks. Another familiar could be a toad, similar to Neville's Trevor. These familiars often play important roles in the fan - created stories, sometimes having magical powers that go beyond what we see in the original books.
In Harry Potter fanfiction, some rare familiars could be a phoenix. It's extremely rare in the normal wizarding world, and in fanfic, it might be given to a special character as a familiar, symbolizing great power and rebirth.
Ravens are sometimes portrayed as very intelligent familiars in Harry Potter fanfiction. They can understand complex instructions and even help their owners with their studies at Hogwarts. For instance, they might find rare books in the library by following the scent of old parchment.
In some Harry Potter fanfictions, serpent familiars are often portrayed as mysterious and powerful. They can be shown as having a deep connection with their owners, almost like an extension of their magical selves. For example, they might be able to sense danger before their owners do and act as protectors.
It can change the power dynamics. For example, if Harry has multiple familiars, he might be more powerful in battles or challenges. His familiars could work together to give him an edge, like one familiar could scout ahead while another protects him.
Well, in Harry Potter familiars fanfiction, there are often ideas about familiars with special powers. Some might have the power to teleport their wizard owners short distances in times of danger. And then there are those that can sense dark magic from afar, acting as an early warning system for their masters. It's also cool when fanfictions explore how familiars interact with Hogwarts itself, like they can find secret passages that even the Marauder's Map doesn't show.