Maybe in the fanfiction, an evil organization manages to kill Pikachu in a cruel experiment. This angers Ash and all the good - hearted trainers, who then team up to take down the organization. Or it could be that Pikachu dies in a natural disaster that strikes the Pokemon world, and the story then follows how the other Pokemon and humans work together to rebuild and also remember Pikachu.
One possible plot could be that Pikachu sacrifices itself to save Ash from a powerful enemy. Ash then has to deal with the grief and also tries to find a way to bring Pikachu back. Another could be that there's a mysterious disease that spreads among Pokemon and Pikachu is one of the victims. This leads to a search for a cure and also a mourning period for the beloved Pokemon.
One possible plot could be a race between Porygon and Pikachu. Since Porygon can move quickly in digital spaces and Pikachu is super fast, they could compete in a unique race. Maybe the prize is a rare Pokemon item.
I'm not sure specifically which fanfiction about Pikachu being dead you're referring to. There could be many different interpretations in such a story. It might explore the reactions of other Pokemon characters, like Ash, who would be devastated. Maybe it delves into the impact on the Pokemon world as a whole, such as how the ecosystem of Pikachu's habitat would change without them.
One possible plot could be that a fisherman is out at night fishing. He gets his line hooked on something strange in the water. As he tries to reel it in, he discovers it's an old, cursed object. Then, as the night falls deeper, he starts to experience strange apparitions and terrifying events related to the object.
In a more complex story, there could be a curse placed on Pikachu by an ancient Pokemon spirit. This curse gradually weakens Pikachu over time. As it gets sicker, Ash tries everything he can to find a cure. But in the end, Pikachu's body gives out. Ash is left to deal with the grief, and he embarks on a journey to find a way to break the curse and bring Pikachu back.
One interesting plot could be Pikachu and Snivy teaming up to explore a mysterious new region in the Pokemon world. They encounter new Pokemon species and have to work together to overcome various obstacles like difficult terrains and powerful wild Pokemon.
One interesting plot could be that the female Pikachu has unique powers. For example, she can communicate with other Pokémon in a special way that helps Ash in his battles. Maybe she can understand the thoughts of Legendary Pokémon, which gives Ash an edge in tough situations.
One interesting plot could be Pikachu getting tickled by its trainer as a form of play. This shows the close bond between them. Another might be Pikachu tickling other Pokemon during a friendly gathering in the Pokemon world, which could lead to a lot of laughter and fun among the different species.
One possible plot could be Sakura trying to get an autograph from Uxumaki. She might go on a journey to find Uxumaki and face many obstacles along the way.
Perhaps Teddy is an artist who is strangely inspired by skulls. In the fanfiction, Teddy uses skulls as models for his art, but as he delves deeper into this obsession, strange things start to happen around him. He might start seeing visions related to the skulls, and his art takes on a life of its own. It could be a psychological exploration of an artist's mind and his relationship with a rather macabre subject.
One possible plot could be that Ash finds a lost Riolu in a forest. He decides to take it under his wing and train it. Along the way, they face off against a group of poachers who are after Riolu for its rare abilities.