A great plot could involve a world where Skin Pokemon are the outcasts because their changing abilities are seen as untrustworthy. A group of trainers decides to prove that Skin Pokemon are just as loyal and worthy as any other type. They form a sort of rescue team for Skin Pokemon in danger and work towards changing the perception of these unique creatures in the Pokemon world.
You can start by giving them distinct goals related to Skin Pokemon. For example, a character could be a scientist obsessed with studying the genetic makeup of Skin Pokemon to understand their shape - shifting abilities. Another way is to give them unique personalities. A trainer who is extremely shy but becomes bold when with their Skin Pokemon can be an interesting character.
Well, a plot could revolve around Janine being involved in a Pokemon tournament where she uses her unique Poison - type Pokemon in unexpected ways. She might face some opponents who underestimate her because of her small stature but she proves them wrong with her brilliant strategies. Or perhaps a story where Janine discovers an ancient Pokemon artifact that has the power to control all Poison - type Pokemon and she has to protect it from evil forces.
One idea could be that Goku arrives in the Pokemon world by some sort of interdimensional rift. He might be confused at first but then start to explore the concept of Pokemon battles. He could use his martial arts skills to train Pokemon in a unique way, like teaching them special combat moves. For example, he could train a Pikachu to use a move similar to his Kamehameha, but in a more Pokemon - friendly version, like an electric blast with a similar charging motion.
Maybe a fanfic where a trainer gets transported into the Pokemon world from our own world. They have to quickly learn the rules and make friends with Pokemon to find a way back home while also exploring the different regions and their unique Pokemon.
One idea could be a Pokemon scientist discovers a new type of Pokemon evolution that is triggered by an unusual environmental factor. For example, a certain type of rare crystal found deep in a cave that causes a Pokemon to evolve into a form never seen before. Another plot could involve a scientist trying to find a way to communicate with Pokemon on a deeper level, perhaps by creating a device that can translate their thoughts. Or, a Pokemon scientist might be on a quest to understand why some Pokemon have unique abilities that seem to go against the known laws of Pokemon biology.
A great plot could involve a group of friends in Alola who enter a Pokemon tournament with their underdog team. They face tough opponents but through their bond with their Pokemon and some clever strategies, they start to make a name for themselves in the tournament. Along the way, they also learn more about the different Alola Pokemon species and their habitats.
Well, you could have a story where a new type of Pokemon is discovered that has vampire - like characteristics, like draining the energy of other Pokemon instead of blood. The main character, a young trainer, has to figure out how to deal with this new threat. Or perhaps there's a vampire Pokemon that was once a normal Pokemon but was cursed. It then tries to find a way to break the curse while befriending a group of trainers.
One idea could be Jasmine going on a journey to find a rare steel - type Pokemon to strengthen her team. Another could be her mentoring a young trainer who has an affinity for steel - type Pokemon. Maybe she could also get involved in a mystery related to a strange steel - type Pokemon behavior in her hometown.
One idea could be exploring the backstory of how Professor Oak started his research on Pokemon. Maybe he had a special encounter as a young trainer that inspired him to study Pokemon evolution and behavior.
One idea could be a baby Pokemon getting lost while wearing diapers and the other Pokemon in the area have to help it find its way back home. Another could be a trainer who discovers a rare Pokemon in diapers and has to figure out how to take care of it while also protecting it from those who might want to steal it for its rarity.