It could be a young and ambitious trainer who dreams of becoming the champion of the Ruby Scar region. This character would start with a basic Pokemon but through hard work and determination, grow stronger.
One idea could be to focus on a new trainer in the Ruby Scar region who discovers a rare and powerful Pokemon that has been lost for centuries. This Pokemon could hold the key to an ancient mystery that the trainer then sets out to solve.
Brendan and May are popular as they represent the players' experience in the game world. People like to expand on their adventures, give them new challenges, and develop their relationships with other characters. Among the villains, Team Magma's Maxie and Team Aqua's Archie can be really popular. Their extreme ideas about changing the world for their respective Pokemon (Groudon for Maxie and Kyogre for Archie) create a lot of room for interesting storylines in fanfiction. Additionally, Wally, the shy but determined trainer, is also a favorite in some fanfictions as he has a lot of potential for character growth.
The main character could be a young trainer named Ash. He's always full of energy and has a Pikachu by his side. His best friend, Gary, could also be a main character. Gary is a bit of a rival but also a great friend. And then there could be Misty, a strong - willed girl who has a love for water - type Pokemon. They could all get into various adventures at the high school.
One interesting plotline could be a trainer's journey in the Hoenn region with a unique team composition. For example, a trainer might focus on using only underrated Pokemon to prove their strength. Another could be a story about the relationship between the legendary Pokemon in Ruby and Sapphire, like how Groudon and Kyogre's rivalry affects the region. And there might also be a plotline where a character discovers a hidden power within themselves while exploring the Hoenn region's mysteries.
A young and inexperienced trainer who discovers they have latent psychic abilities and uses them to bond with their psychic Pokemon. This character could grow throughout the story as they learn more about their powers.
It could be a scientist who is involved in the study of Pokemon genetics. While trying to understand the mechanics of evolution better, they accidentally stumble upon the new evolution and then become involved in the events that unfold as a result, both in the scientific and the trainer communities.
It could also be an experienced pokemon trainer who has seen a lot in their travels. After encountering a mirage pokemon by accident and realizing how different and powerful they are, they become determined to become the mastermind in the world of mirage pokemon. They use their existing pokemon training skills and knowledge to study these special pokemon, making them a formidable force in the fanfiction.
The main character could be a talented pokemon stylist. They have a passion for making pokemon look their best with unique haircuts. They travel around different regions to learn new haircut techniques and to show off their skills on various pokemon.
It could be Ash. He's the classic Pokemon protagonist and has been through so many trials already. His will has been tested countless times, like when he faced the Elite Four or when he had to rescue his Pokemon from Team Rocket. In this fanfiction, he could face a new kind of test that really pushes his will to the limit.
A Pikachu could be a great main character. Pikachu is popular and has a lot of potential for character growth. It could start as a timid Pokemon but become a strong leader during the uprising.