One idea could be a story where a cat discovers it has the power to talk to other animals and they all team up to save their neighborhood from a construction project that would destroy their habitats. Another could be a dog that gets lost in a magical forest and has to find its way home while befriending strange forest creatures.
Well, you could write a pet fanfiction about a parrot that has lived through many generations of a family and has all sorts of secrets and stories to tell. Maybe it witnessed a hidden treasure being buried in the backyard ages ago and now it's trying to get the current family members to find it. Or perhaps a hamster that suddenly finds itself in a world of giants (humans) and has to adapt and figure out how to communicate with them to get back to its cozy cage.
A great pet fanfiction concept could be about a group of pets in an animal shelter. Each one has a different backstory and dream. One dog was a former police dog who got injured and now is looking for a new purpose. A cat was abandoned by its rich owners when they moved away. They all form a bond in the shelter and work together to find their forever homes, facing all sorts of challenges along the way like mean shelter workers and limited resources.
One idea could be to focus on the adventures of a unique pet in the Caeria world. For example, a magical pet that can communicate with different species. It could go on a journey to find a lost relic that has the power to save its home.
One interesting idea could be the nature of Voldemort's pet. Maybe it has some unique magical abilities that are different from ordinary magical creatures. For example, it could have the power to communicate telepathically with Voldemort.
One idea could be that Fox McCloud discovers an injured alien pet during one of his space missions. He decides to take it in and nurse it back to health. As he does so, the pet starts to show unique abilities that end up helping Fox and his team in unexpected ways during battles.
A great concept for 'Pet Boy of Fairy Hills' fanfiction could be a conflict between different factions in the Fairy Hills. The 'Pet Boy' could get caught in the middle of it. He might have to choose a side or find a way to bring peace. You could also introduce a mystery element, like a series of strange events happening in the Fairy Hills that the 'Pet Boy' is determined to solve.
One idea could be a story where a young wizard discovers a dragon egg in the Forbidden Forest. He decides to secretly hatch it and raise the dragon as his pet. As the dragon grows, he has to constantly hide it from the Hogwarts professors, especially Hagrid who has his own ideas about magical creatures.
One idea could be a pet that has special abilities which help the kids in their escape plans. For example, a pet bird that can scout areas without being noticed and report back to the children.
One idea could be exploring the backstory of the burial ground in more detail. Maybe there was an ancient curse that led to its creation. Another could be focusing on a character who narrowly escaped the evil of the Pet Sematary and how it changed their life. A third idea might be to create a fanfiction where the animals in the Pet Sematary have a secret society and try to fight against the dark forces that control the place.
One idea could be exploring the backstory of the shop owner. Maybe he has a tragic past that led him to open this strange pet shop. Another could be a customer who gets a pet that changes their life in unexpected ways, like a small pet that actually helps them solve a big mystery in their town. Or perhaps a story about a group of friends who visit the pet shop together and each has a different encounter with the creepy pets.
A plot could be that Snape's pet is a phoenix, which is a very rare and powerful magical creature. Harry Potter is intrigued by this phoenix and tries to get closer to it. Snape is initially against this but as the story progresses, he sees that Harry has a pure heart and allows him to interact with the phoenix. This could lead to a bond forming between Harry and Snape through their shared interest in the phoenix.
One idea could be that Severus discovers Hermione has a unique magical ability that only he can help her control, and in the process, he starts to see her as more than just a student. Another could be that Hermione is turned into a small, magical creature by accident, and Severus takes her in as a pet to protect her until she can be turned back. And perhaps, Severus initially resents having to take care of her but gradually grows fond of her presence.