Well, if Charizard takes a different path in the fanfic, it might change the entire dynamic of the story. Maybe it forms a special bond with a different trainer or discovers a hidden talent.
One possible fanfic could be about Ash starting his journey with Snivy. Maybe it focuses on their initial struggles to understand each other. Ash, being used to more energetic starters, might find Snivy's calm and sometimes aloof nature a bit difficult to deal with at first. But as they face various Pokemon battles together, they gradually build a strong bond.
One possible plot is that Charizard gets sick and the only cure is a special lemon - based potion. The trainer has to search far and wide for the right lemons and the ingredients to make the potion. Along the way, they face challenges from other Pokemon who also want the lemons for their own reasons.
In a 'pokemon getting a starter fanfic', aside from the trainer and the professor, there might be the trainer's family members. They could be supportive or skeptical of the trainer's pokemon journey. Another common character could be an older, more experienced trainer who acts as a mentor to the newbie. This mentor might give advice on how to train the starter pokemon and deal with various challenges in the pokemon world. There could also be the Pokemon Center nurses who play a role in healing the starter when it gets injured during battles or adventures.
One possible plot is that Treecko gets separated from its trainer early on. It then has to find its way back, facing many dangerous Pokemon on the way. During this journey, it learns new skills and becomes more independent.
Well, one possible plot could be that the protagonist starts their Pokemon journey with a Milotic. They might face challenges in training it as Milotic is a rather elegant and somewhat difficult to train Pokemon. Maybe they enter a Pokemon beauty contest where Milotic's natural grace gives them an edge, but they also have to deal with jealous opponents who try to sabotage them.
Well, for one thing, Milotic is not your typical starter Pokemon in the official games. So, a fanfic that starts with it already has an element of novelty. It can explore the trainer's journey in a different way compared to if they had started with a more common starter. The fanfic could also delve into the lore behind Milotic, like its evolution from Feebas, and how that backstory affects the trainer - Milotic relationship and the overall plot of the story.
I think Grookey is a great starter for the Pokemon Sword story. It has a strong start in terms of its attacks and evolves into a very powerful final form. It can easily handle the early - game battles which are important for progressing through the story.
Perhaps it's a story where a trainer uses a lemon - scented item to attract Charizard. And then they go on a journey together, with the lemon becoming a sort of symbol or good luck charm throughout their adventures. It could also involve other Pokemon being curious about this lemon - associated Charizard.
One interesting plot could be a young trainer who gets a starter that is considered weak, like a Caterpie, but through hard work and unique training methods, it evolves into a powerful Butterfree that surprises everyone. Another could be a trainer who has an unexpected bond with their starter right from the start, for example, a Pikachu that refuses to go into a Pokeball and they form a really close relationship like Ash and his Pikachu in the anime.