One possible plot could be that Ash initially joins Team Rocket by mistake. He gets caught up in one of their schemes and ends up traveling with them for a while. Along the way, he tries to convince them to change their ways and use their skills for good. For example, he might show them how they could use their knowledge of Pokémon capture to help rescue Pokémon in danger instead of stealing them.
In the fanfiction, it could be that Ash is cursed and the only way to break the curse is to complete a journey with Team Rocket. As they travel together, they face many challenges that force them to work together. Team Rocket starts to see Ash in a new light and begins to question their own motives and actions.
One possible plot could be Ash getting brainwashed by Team Rocket into thinking his Pokémon friends are his enemies. Then he starts to help Team Rocket in their schemes against other trainers. This would create a lot of conflict as his real friends try to snap him out of it.
Jessie and James are the obvious ones. They are the main members of Team Rocket. Jessie could be constantly trying to outdo Ash in Pokémon battles or contests of skill. James, on the other hand, might be more conflicted about having Ash around. He could secretly admire Ash's kindness towards Pokémon and start to have second thoughts about their Team Rocket activities.
The plot might involve a power struggle within Team Rocket. Ash and Misty could be brought in because they possess certain skills or knowledge. For example, Ash's bond with his Pokémon could be seen as a valuable asset. Misty's understanding of water - type Pokémon might also be desired. However, they soon realize that they are being used in a power play between different factions of Team Rocket, and they must decide which side to take or find a way to break free from the whole mess.
Well, one plot twist could be that Ash is actually a double agent. He pretends to join Team Rocket to gather information for the good guys. Maybe he discovers a big secret plan of Team Rocket, like they're planning to steal all the Pokeballs in a certain region. This would completely change the power dynamic and put Team Rocket on high alert.
There could be a fanfiction where Team Rocket finally manages to steal all of Ash's Pokémon. But instead of using them for evil, they realize the strong bond between Ash and his Pokémon and start to have a change of heart. This would be a great exploration of the themes of redemption and the power of friendship in the context of the Ash vs Team Rocket dynamic.
One possible plot could be that Ash and Dawn are traveling together when Team Rocket attacks. Ash might use his Pikachu to fend off their initial attacks. He could then come up with a clever strategy, like using the environment to his advantage. For example, if they are near a body of water, he could make Team Rocket's Pokémon slip. Dawn, on the other hand, could use her knowledge of Pokémon contests to distract Team Rocket with some flashy moves from her Pokémon. In the end, Ash and Dawn manage to escape and continue their journey.
One possible plot for a fanfic where Ash joins Team Rocket could be that there's a powerful and mysterious Pokémon that only Team Rocket knows how to find. Ash, desperate to catch this Pokémon, makes a deal with them to join. However, once he's part of the team, he discovers that their methods are far more cruel than he expected. He then has to battle his own conscience as well as the other members of Team Rocket to either stop their plan or find a more ethical way to catch the Pokémon.
One idea could be that Ash gets transformed into a Pokémon and has to figure out how to communicate with his friends. Another could be that Team Rocket manages to use a new device to transform Pikachu into a different type of Pokémon. Maybe Ash and Team Rocket end up having to team up when a new, more powerful villain emerges who wants to transform all Pokémon into mindless servants.
Yes, in some Team Rocket fanfictions, Ash can be depicted in various ways that might involve him having some sort of connection to Pokémon in a different light. Maybe he could be experimented on by Team Rocket to gain Pokémon - like abilities, or be transformed into a Pokémon - like being in a very creative and out - of - the - box fanfiction concept.
It could lead to some really unexpected and exciting plot twists. Ash's alignment with Team Rocket would completely change the dynamics of the story.