A Charmander could be a great choice. It's a classic and powerful Pokemon. She could raise it from a small, timid lizard to a strong Charizard. This would mirror Ash's own growth with his Pokemon. Also, it would give her a strong partner for battles and adventures. And it could have a special bond with her, similar to how Ash's Pokemon had with him.
Maybe she would have a Sylveon. It's a beautiful and fairy - type Pokemon. Since she's a new generation, having a more modern and unique Pokemon like Sylveon would be interesting. It could represent her own style of Pokemon training, which might be more focused on friendship and harmony with Pokemon, rather than just battles.
She might have a Bulbasaur. It's a classic starter Pokemon and it could symbolize a connection to Ash's early days as a trainer. Also, Bulbasaur can be very strong and useful in battles as well as contests with its cute appearance.
She might have a Eevee. Eevee is a very adaptable Pokemon and could evolve in different ways depending on her experiences, just like her character would develop in the story.
A Vulpix might be a good choice for her. It's a Fire - type Pokemon, which shows her having some strength. Vulpix is also very elegant and could symbolize her grace. And in the fanfiction, she could have a special bond with her Vulpix, like it was a gift from a family member when she was young.
The fanfiction could focus on Ash's daughter's relationship with her father. Ash could teach her all he knows about Pokemon battles and care. They might go on adventures together, and she could learn valuable lessons from him. For example, how to befriend wild Pokemon or how to strategize in battles. It could also show how Ash has changed as a father compared to his days as a young trainer.
He could have a Froakie. It's a common and cute starter in Kalos. Maybe also a Skiddo for traveling across the Kalos landscapes. And a Bunnelby would be a nice addition for its digging abilities.
If Red was Ash's father in a Pokemon fanfic, Ash might start with a Pikachu like in the original series, but it could be a special Pikachu that Red had some connection to. Maybe it was a Pikachu that Red had trained briefly or had a unique bond with.
In Pokemon fanfiction, the idea of Ash and Dawn having a daughter can lead to many interesting storylines. It could involve their daughter inheriting their love for Pokemon battles. Maybe she'd start her own journey, with Pikachu or one of Dawn's Pokemon as her partner.
Well, in such a fanfiction, Ash might experience the life of a Pokemon in a very different way. He could understand their thoughts and feelings more deeply. Maybe he'd have to learn how to use Pokemon moves in his new form, which would be a really strange and exciting adventure for him.
Pikachu could be a great choice as it has been Ash's iconic Pokemon. It would create a strong connection between the daughter and her father's journey. Another option could be a Eevee. Eevee has the potential to evolve into different types, which would offer a lot of possibilities for her journey and battles.
Ash could have adventures like exploring a hidden part of the school that has a connection to a rare Pokemon. Maybe there's an old library in the school that holds secrets about legendary Pokemon, and Ash stumbles upon it during a game of hide - and - seek with his new friends.