One idea could be to explore an alternate universe where the main characters in Pokemon BW have different starters. For example, if the protagonist started with a Snivy instead of a Tepig. Another could be a story where Team Plasma has a different motive, like trying to protect Pokemon in a more extreme way that the trainers don't understand at first. Maybe a fanfic could also focus on the relationship between a trainer and a very rare Pokemon they encounter during their journey in Unova.
Well, you could write a 'pokemon bw fanfic' where the Pokemon Gyms in Unova have new and unique challenges. Instead of the normal battles, they could be based on solving puzzles with the help of your Pokemon. Or perhaps a story about a Pokemon that has the ability to travel between different regions in the Pokemon world and how it affects the story of BW. You could also do a fanfic centered around a character who wants to create a new type of Pokemon training method that shakes up the traditional ways in Unova.
One idea could be exploring an alternate universe where the protagonist starts with a rare and unique Pokémon that's not available as a starter in the original game. Another could be a story about a Pokémon trainer who has the ability to communicate with Pokémon in a more in - depth way than normal, and how that changes their journey in the Unova region. Maybe a fanfiction about a group of Pokémon trainers coming together to solve a mystery that threatens the balance of the Unova region.
One idea could be that Ash and Bianca team up for a special Pokemon tournament in the Unova region. They face tough opponents together and along the way, their friendship deepens into something more. Ash could teach Bianca some new battle strategies he learned from his previous travels, and Bianca could introduce Ash to some unique Unova Pokemon.
One interesting story could be about Ash's journey in the BW region with some unexpected Pokemon partners. Maybe he meets a rare and powerful Pokemon that no one has ever seen before in that region and they form a special bond. This could lead to him facing new and challenging Gym Leaders in unique ways.
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.
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.
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.