One idea could be a story where a fairy - type Pokemon befriends a group of lost Pikachu and helps them find their way home. It could involve using its magic powers to protect them from various threats in the forest.
Well, you could have a fanfiction where Harry discovers a hidden fairy - tale book in the Hogwarts library that transports him into different fairy - tale scenarios. In each scenario, he has to use his wizarding skills to solve problems and get back. Or perhaps a story about how the magic in the Harry Potter universe combines with the magic of fairy tales. For instance, the Sleeping Beauty's curse could be related to a dark wizard's spell in the Harry Potter world. Also, a fanfiction about a Harry Potter character writing their own fairy tale using magic would be interesting.
How about a plot where a Pokemon is cursed with a Fairy Tail - type of dark magic? The Pokemon becomes uncontrollable and starts causing chaos in both worlds. A group of Pokemon experts and Fairy Tail wizards must work together to find a way to break the curse. This could involve traveling to ancient and mysterious places in both universes, like the ruins of an old Pokemon temple or a forgotten Fairy Tail library where they might find the solution to the curse.
Another plot could be inspired by Little Red Riding Hood. A young apprentice is sent to take some herbs to an elder who lives on the outskirts of the territory. On the way, she meets a strange cat who tries to lead her astray. But she remembers her warrior training and outsmarts the cat. In the end, she realizes the strange cat was a rogue trying to find out the Clan's secrets.
One idea could be that the Fairy Tail guild members discover a portal to the Pokemon world. They then team up with different Pokemon trainers to stop an evil organization that's trying to take over both worlds. For example, Natsu could befriend a Charizard and use its fire power in combination with his own to fight enemies.
One idea could be that the Fairy Tail mages discover a new world filled with Pokemon. They could form teams with the Pokemon and use their magic in combination with the Pokemon's abilities to fight against a common enemy. For example, Natsu could team up with a Charizard and use his fire magic along with Charizard's fire breath to create super - powerful fire attacks.
One idea could be a Pokemon girl trainer who somehow gets transported to the Fairy Tail world. She could use her Pokemon skills and her Pokemon to help the Fairy Tail guild in battles, like using a water - type Pokemon to put out fires during a fight in a village. Another could be a Fairy Tail mage who discovers Pokemon eggs and starts to raise them, learning about the unique bond between a trainer and a Pokemon.
A really interesting plot would be if the world of the fanfiction was facing a threat that only the fire dragon powers could stop. But the catch is that the current fire dragon slayers have to combine their powers in a way they've never done before. They would have to overcome their differences and learn to work together, all while dealing with the increasing danger to their world.
One idea could be a modern retelling where the fairy tale characters live in a contemporary city. For example, Cinderella could be a struggling artist who meets her prince at an art gallery opening. Another plot could involve a crossover between different fairy tales, like Snow White teaming up with Red Riding Hood to defeat an evil witch that threatens both their kingdoms.
One interesting RWBY fairy tales fanfiction could be a retelling of Cinderella but set in the RWBY universe. Maybe Ruby is the Cinderella figure, with her red cloak as her signature item. Another could be a Snow White - like story where Weiss takes on the role of Snow White, and the Grimm are like the evil forces in the fairy tale. There are also fanfictions that blend multiple fairy tales, like mixing elements of Little Red Riding Hood and Beauty and the Beast in the RWBY world.
One idea could be a hybrid of Pikachu and Eevee. This hybrid could have the cute appearance of both, with Pikachu's lightning - based powers combined with Eevee's ability to evolve into different forms. It could be a central character in a story where it's trying to find its place in the Pokemon world, being different from the normal Pokemon.