Ash could develop his character in Sinnoh by becoming more strategic in his battles. Since Sinnoh has a variety of strong and unique Pokemon, he'd need to think more carefully. Misty could develop by becoming more independent. Maybe she takes on some solo adventures in Sinnoh, away from Ash for a bit, and this helps her grow as a trainer.
In a fanfic about Pokemon working in Sinnoh with skill, trainers could play a crucial role. They might train their Pokemon to perform specialized tasks. The story could revolve around a trainer who discovers new ways to utilize their Pokemon's skills in Sinnoh. Maybe a Pikachu using its electric skills to power up machinery in an old mine in Sinnoh.
Well, in a fanfic, a Pokemon like Bulbasaur could use its grass - type skills to help with gardening in Sinnoh. It could plant and grow all kinds of beautiful flowers and useful plants.
Ash may develop his skills further in Sinnoh fanfictions. He could become more strategic in battles, learning from the different types of Pokémon and trainers in Sinnoh. May, on the other hand, might expand her knowledge of Pokémon contests, incorporating Sinnoh - style elements into her performances. Their experiences in Sinnoh help them grow both individually and as friends.
In some fanfictions, Ash and May might get involved in a mystery in Sinnoh. For example, strange events are occurring that are affecting Pokémon behavior. They work together to solve the mystery, with Ash using his battle skills and May her knowledge of Pokémon contests. As they dig deeper, they find that an ancient power from Sinnoh's past is being misused.
Perhaps there is a threat to Sinnoh that only Ash's old Pokémon can help solve. Some kind of ancient evil that has knowledge of Ash's past Pokémon battles. Ash and his old Pokémon then have to work together to defeat this threat. They might need to combine their old strategies with new ones they learn in Sinnoh to succeed. And along the way, Ash might meet some of his old friends who are also in Sinnoh and they help him in his mission.
One plot idea could be Ash and Misty getting separated from their group in Sinnoh and having to rely on each other to survive in a strange, new area. They could encounter a rare and powerful Pokemon that neither of them has seen before. Another idea is that they discover an ancient mystery in Sinnoh related to a type of Pokemon evolution that was thought to be lost. This could lead them on a journey to uncover the truth and help a particular Pokemon evolve in a new way.
Once, I was at a concert. There was a couple in front of me who seemed to be having their own little dance party. They were completely out of sync with the music and each other. The guy was doing some really wild moves, and the girl was trying to be all elegant. It was a strange and funny sight. People around were trying not to laugh out loud, but it was really hard.
My friend and I were hiking in the mountains. We came across a family of deer. One of the fawns was really curious and started following us. It was so cute. We tried to shoo it away gently because we didn't want to disrupt it too much, but it just kept coming closer. Eventually, its mother called it back and we all had a good laugh about our little furry follower.
His first Sinnoh Pokémon could be a Chimchar. Imagine Ash finding Chimchar being bullied by some other Pokémon. Ash steps in and Chimchar decides to join him. Chimchar's energetic and mischievous nature would add a lot of fun to Ash's Sinnoh adventures as it grows and evolves into an Infernape.