In a fanfiction where Ash joins Team Rocket, it could lead to some really interesting storylines. Ash has a lot of knowledge about Pokémon training that Team Rocket lacks. He could potentially teach them new techniques, but at the same time, his moral compass would be constantly at odds with their devious ways. Maybe he joins them because he's somehow tricked or he has his own secret plan to take them down from the inside. It would be a great opportunity to explore different aspects of his character and how he adapts to this new situation.
In a Pokemon Red join Team Rocket fanfic, the main character could be a disillusioned trainer. Maybe they've lost a few too many battles and are looking for a new way to gain an edge. Team Rocket seems like an alluring option. They join up and are immediately thrust into the world of illegal Pokemon trading. However, they soon meet a friendly Pokemon that shows them kindness despite their new allegiance. This makes them question their decision to join Team Rocket and they start to think about how they can use their new position to actually help the Pokemon instead of harming them.
Maybe there's a rogue Pokemon trainer. This trainer is jealous of Dawn's skills and the attention she gets. When Dawn joins Team Rocket, this trainer sees it as a chance to expose her as a fraud. He or she then tries to stop Dawn and Team Rocket's activities, thinking that they are up to no good, which they are, but the trainer has his own self - centered motives.
One interesting Pokemon Team Rocket fanfiction could be about a Team Rocket member who has a change of heart. For example, they might start to see the beauty in the relationship between trainers and their Pokemon and decide to secretly help the heroes instead of causing trouble.
One thing that would happen is that his Pokémon battles would take on a whole new meaning. Instead of battling for the sake of becoming a Pokémon master, he might be battling to further Team Rocket's goals. His Pokémon would have to adjust to this new purpose. Also, Ash would probably have to wear Team Rocket's uniform, which would be a really strange sight for fans who are used to seeing him in his normal get - up.
One possible storyline is that Dawn joins Team Rocket thinking it's a legitimate Pokémon training organization at first. But as she gets deeper into it, she discovers their true evil nature. Another could be that she is brainwashed by Team Rocket into joining them. Her friends then have to find a way to break the brainwashing. A third storyline could be that she joins willingly because she has some sort of vendetta against the Pokémon League and sees Team Rocket as a way to get revenge.
One common theme is redemption. Many fanfictions explore the idea of a Team Rocket grunt realizing the error of their ways and trying to turn their life around. For example, they might meet a kind - hearted Pokemon trainer who makes them see the harm they're causing.
Archive of Our Own (AO3) also has some excellent Pokemon Team Rocket fanfiction. The site has a well - organized tagging system, which makes it easy to filter out stories that are not to your taste and find ones that are really good.
The main characters might not only be human trainers. Some Pokemon could take on leading roles. For example, a powerful and wise Charizard could be a main character. It might have been trained by a famous trainer in the past but now fights independently against Team Rocket. There could also be a group of Eeveelutions that are the main focus. They have different abilities and personalities, and together they form a force to be reckoned with against Team Rocket. Alongside them, there could be a trainer who acts as a guide or coordinator for their efforts.
One interesting storyline could be Team Rocket actually helping Ash in a dire situation. Maybe they realize that a greater evil is about to destroy the Pokemon world and they decide to team up with Ash for once. Their skills in stealing and sneaking around could be useful in gathering information about this new threat.