One possible plot could be a person suddenly wakes up in the Pokemon world as their favorite Pokemon. They then have to figure out how to survive in this new world, make friends with other Pokemon, and avoid being caught by trainers. Maybe they also discover they have some special abilities that are unique to them even among Pokemon.
A plot could be that the character, who has turned into a Pokemon, is initially confused and scared. They find themselves in a Pokemon daycare and have to learn the ropes of being a Pokemon from the young Pokemon there. Along the way, they encounter different types of Pokemon with various personalities and quirks. They might also enter Pokemon contests, not as a trainer but as a participant, and have to use their new Pokemon skills to win.
Well, perhaps the story could start with a strange accident that turns the main character into a rare and powerful Pokemon. As a result, they are hunted by an evil organization that wants to use their power for bad things. The character then has to team up with a group of friendly Pokemon and trainers to fight against this organization and find a way to turn back into a human.
It could be an ordinary teenager. Teenagers are often the main characters in fanfiction because they can have relatable insecurities and a thirst for adventure. They might be a bit of a misfit in their own world and then find a new sense of purpose when they turn into a Pokemon.
Another idea is that there is a tournament in which both Si and Sabrina participate. However, there are some underhanded trainers who are using dark psychic powers to manipulate the outcome. Si and Sabrina team up to expose these cheaters. As they work together, they develop a deeper bond. Sabrina teaches Si some psychic techniques to use in battles, and Si shows Sabrina the value of having a diverse team of Pokemon rather than just focusing on psychic types.
The way Ash adapts to Pikachu's instincts could be really interesting. He might find himself being more drawn to shiny objects or having an urge to store food in a certain way. And his relationship with his own Pikachu (if it still exists in the story) would be very different. They could become like equal partners instead of trainer - Pokémon.
Perhaps Naruto arrives in the Pokemon world during a big crisis, like an evil team is trying to take over. Naruto, with his never - give - up attitude, decides to help. He teams up with some powerful Pokemon, and his Rasengan technique could be translated into a super - powerful Pokemon move. His ninja stealth could also be used to gather intelligence on the bad guys.
A really interesting character could be a mysterious old trainer who has knowledge about a long - lost Pokemon type. He could guide Si and Ash on their journey. Another could be a young Pokemon researcher who is studying the behavior of a particular group of Pokemon that Si and Ash keep encountering. And a Pokemon breeder who has a special way of breeding strong Pokemon could also be an exciting addition.
There are fanfictions where a male SI (self - inserted) character teams up with some rare and powerful Pokemon. For example, he might find an injured Eevee and nurse it back to health, and then they form an unbreakable bond. This Eevee could later evolve into an unexpected form based on their adventures together. In some stories, the male SI might also get involved in the complex politics between different Pokemon gyms.
One interesting plot could be that Ben, using his Omnitrix, accidentally lands in the Pokemon world. He teams up with Ash and Pikachu to stop an evil organization that is trying to use both Pokemon and alien technology. For example, they might be creating hybrid creatures using Pokemon DNA and alien powers. Ben's different alien forms could have unique interactions with the Pokemon. His Four Arms form could be really strong in Pokemon battles, while his XLR8 form could be used to quickly traverse the Pokemon world to reach different areas in time to stop the villains.
One possible plot could be that Ash is transformed into a rare and powerful Pokemon like Mewtwo. He then has to navigate the Pokemon world from a different perspective. He discovers new abilities and strengths he didn't know about before. And he uses his knowledge of being a trainer to communicate with other Pokemon and form alliances to face the challenges that come his way.
Maybe Ursula is a Pokemon researcher in this fanfiction. Naruto, with his curious nature, decides to help her in her research. Along the way, they discover a new type of Pokemon that has special powers. Their adventure to understand and protect this new Pokemon could form the basis of the story. It would involve Naruto using his combat skills and Ursula her knowledge of Pokemon.
One possible plot could be that the Pokemon and Justice League members have to team up to stop an evil force that is trying to take over both the Pokemon world and the cities protected by the Justice League. Maybe a powerful, shadowy villain has discovered a way to use Pokemon powers in the human world in a very destructive way, and only by combining the unique abilities of the Pokemon and the superpowers of the Justice League can they hope to defeat this new threat.