One idea could be exploring the backstory of the main character's magical powers in more depth. Maybe she discovers a hidden origin of her powers that changes her perception of herself.
Another plot could involve a new character entering the story, a mysterious traveler who has knowledge about an ancient prophecy related to the Girl of Fire and Thorns. This new character could either help or hinder the protagonist on her journey. For example, they could initially seem helpful but later be revealed to have their own motives that conflict with the main character's goals.
One idea could be exploring a different origin for the main characters. For example, what if Feyre was from a long - lost clan in the mortal world with unique powers? Another could be a 'what if' scenario where Tamlin didn't make the mistakes he did in the original story and he and Feyre had a more harmonious relationship. Or perhaps a story where the Night Court has to face a new, unexpected threat that forces them to form alliances with old enemies.
One idea could be exploring the backstory of a minor character in more detail. For example, a character who only had a brief appearance in the original but has a really interesting family history or a hidden power that could be developed in the fanfic.
One idea could be exploring a different path for the main character's relationship with a key figure. For example, instead of the initial enmity, they could start as reluctant allies from the very beginning. Another plot could involve a new magical threat that the characters have to face together, something that wasn't in the original story.
One idea could be that Fire Boy and Water Girl find a magical forest where the rules of their elements are reversed. Fire Boy has to be careful not to extinguish himself in the overly wet areas, and Water Girl has to avoid drying up in the super - hot spots. They have to work together to find a way out of this strange forest.
Well, in 'naruto rainbow fire fanfiction', a cool plot might be that the rainbow fire is actually a key to a different dimension. Naruto, being the curious and brave ninja he is, accidentally stumbles upon this while on a mission. He then has to figure out how to use the rainbow fire to get back to his own world, all while facing strange creatures and new forms of chakra in this other dimension. Also, the rainbow fire could be related to a prophecy that only Naruto can fulfill, which sets him on a grand adventure.
One idea could be a trainer who discovers a hidden power within the Sacred Fire Pokémon that has been forgotten for centuries. This power could be related to an ancient prophecy that the trainer must fulfill to save the Pokémon world from a new and powerful threat.
One idea could be to explore a different path for a minor character. For example, what if a servant in King's Landing had a secret ability to communicate with animals and used it to gather intelligence. Another could be a story where the magic in the world of Ice and Fire has a different origin than what is known in the original series. Maybe it was brought by an ancient alien race that visited Westeros long ago.
One interesting plot idea could be exploring what would happen if a different student was chosen for the Triwizard Tournament. Maybe a shy and overlooked student gets picked, and they have to overcome not only the tournament tasks but also their own insecurities. Another idea could be a love triangle involving characters that were not part of one in the original story. For example, a friendship between a Hufflepuff and a Slytherin turns into a complex relationship when feelings for Harry Potter get involved.
One interesting plot idea could be exploring what would happen if a minor character, like Gendry, became a key player in the fight against the White Walkers. He has the skills and the unknown parentage which could be a great source for new storylines.
Perhaps Naruto is mistaken for a new student at Hogwarts and is sorted into a house. He then has to deal with the politics of the school while also trying to figure out how to get back to his own world. He might make friends with Harry and the gang, and they all learn from each other's combat styles. For example, Naruto could teach them about hand - to - hand combat, and they could teach him more advanced magic theory.