A great storyline could also be a crossover within the Harry Potter universe. Imagine a situation where characters from the Harry Potter books meet those from the Fantastic Beasts world. Maybe Harry and his friends stumble upon Newt's case of beasts during one of their Hogwarts adventures, and they have to work together to solve a problem caused by a mischievous beast that has escaped.
One interesting storyline could be about the origin of some of the fantastic beasts. For example, a fanfiction might explore how the Hippogriff came to be. Another could be a story that focuses on the relationships between different characters from both series in a new and unexpected way, like a friendship between a Hogwarts student and a wizard from the Fantastic Beasts era.
One idea could be exploring the backstory of a minor character from the series in the fanfiction. For example, delving into the early life of Luna Lovegood's father. Another could be a story where a new magical creature is discovered in the Forbidden Forest and how the Hogwarts students interact with it. Or perhaps a fanfiction where the events of the Fantastic Beasts movies intersect more directly with the main Harry Potter storyline, like Newt Scamander visiting Hogwarts during Harry's time there.
One idea could be that Newt Scamander visits Hogwarts to give a special lecture on fantastic beasts. During his visit, he discovers a hidden magical creature that has been living in the Forbidden Forest for centuries. Harry Potter and his friends get involved in helping Newt study and protect this new discovery.
One possible storyline could be Hermione traveling back in time to the era of Fantastic Beasts. She could use her vast knowledge of magic to help Newt Scamander with his research. Maybe she discovers a new magical creature that was previously thought to be extinct. Another idea is that Hermione gets accidentally transported into the Fantastic Beasts universe and has to find a way back to her own time while getting involved in the local magical politics and helping to protect the magical creatures from dark wizards.
They are interesting because they blend two magical worlds. We get to see how the characters from Harry Potter would react to the new and strange creatures in Fantastic Beasts.
Fantastic Beasts is not a Harry Potter movie. The Harry Potter movies include Harry Potter and the Sorcerer's Stone, Harry Potter and the Chamber of Secrets, Harry Potter and the Prisoner of Azkaban, Harry Potter and the Goblet of Fire, and Harry Potter and the Order of the Phoenix. And Fantastic Beasts was a chapter in the Harry Potter series, written by JK Rowling. The chapter on Magical Beasts mainly tells the story of a wizard named Neet Scamander who uncovers some secrets of the magical world while searching for magical animals.
One idea could be a story where Newt Scamander's magical beasts escape into Hogwarts. The students and teachers have to work together with Newt to recapture them. It would be a chaotic yet fun scenario as the beasts interact with the Hogwarts environment and its inhabitants.
One interesting storyline could be about alternate versions of the Triwizard Tournament. Maybe in the fanfiction, the tasks are even more dangerous and creative, with different characters getting involved in unexpected ways. For example, Neville could be a surprise champion and show his hidden talents during the tasks.
In some fanfictions, Alexstrasza could be a hidden protector of Hogwarts. Since she is a very powerful being, she might have been secretly watching over the school for centuries. When Harry arrives, she reveals herself and offers her assistance, especially in dealing with the dark creatures that lurk around the school and are allied with Voldemort.
Another storyline might involve an Ogron having a unique magical ability that Harry Potter discovers and uses to their advantage. For example, the Ogron could be able to communicate with a certain type of magical creature that holds the key to a powerful spell or a hidden treasure. This would lead Harry and his friends on an exciting adventure to find and utilize this newfound power.