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.
Obviously, Harry Potter himself is extremely popular as the main character. Fans love to write more about his adventures with his familiars from different perspectives.
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.
One idea could be exploring the deeper bond between Harry and his owl, Hedwig. Maybe a story where Hedwig has some secret magical abilities that help Harry in a unique way during a difficult time at Hogwarts.
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.