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.
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.
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 great plot for Pokemon adventure fanfiction might involve time travel. For example, a trainer gets sent back in time to the early days of Pokemon discovery and has to adapt to the primitive training methods while also trying not to disrupt the timeline. Also, a story about a trainer who is cursed to only be able to communicate with Ghost - type Pokemon and has to use their unique abilities to solve mysteries. And a fanfiction where a group of Pokemon break free from their Pokeballs and form a little community in the wild, and the trainer has to figure out how to get them back without using force.
One idea could be a new character arriving at Fairy Hills and having to adapt to the unique living situation. They could face challenges like getting along with the different personalities of the Fairy Tail mages living there.
Maybe Marceline the Vampire Queen teams up with a Dark - type Pokémon in a fanfiction. Since she has a somewhat dark and mysterious personality, it would be interesting to see how she interacts with a Pokémon that shares those traits. For example, she could form a bond with a Umbreon and they could go on adventures together.
One idea could be Metalicana's backstory before he was known in the Fairy Tail world. Maybe exploring his early days as a dragon, his first encounters with other dragons or magical creatures. Another plot could involve Metalicana having a secret mission that is related to the future of the dragon slayers in Fairy Tail. It could also be interesting to have a plot where Metalicana has to team up with some of the Fairy Tail members in a time - travel adventure to save the past and thus ensure the future of the guild.
Another plot could involve a dark mage in the Fairy Tail universe summoning Deathwing to gain power. But the summoning goes wrong and Deathwing is only partially summoned. This weakened Deathwing starts causing destruction while also being hunted by Fairy Tail. The guild then has to decide whether to try and fully summon him to send him back or find another way to deal with him.
A cool plot could be that a powerful artifact in Skyrim is causing chaos and the Fairy Tail members are summoned to find and secure it. Along the way, they meet up with the Dragonborn. Some members might befriend the Dragonborn and help in their battles, while others might be a bit more skeptical and think the Dragonborn is a threat to their own power within the group.
One idea could be that Gojo, with his overpowered abilities, joins Fairy Tail and becomes a mentor figure to the younger wizards. He could teach them new ways to use their magic and help them in battles against powerful foes.