One plotline could be that Ash is on a secret mission for the Elite Four. He has to travel around the Pokémon world, but without revealing his connection to the Elite Four. Another could be that he's in a situation where he has to choose between his friends and his Elite Four duties.
Well, there might be some. You could start by checking out some popular fanfiction websites. Some might have really creative takes on Ash being secretly part of the Elite Four. It really depends on how the author interprets the concept and what kind of story they want to build around it.
In this fanfiction, Ash might face some unexpected challenges before even reaching the Elite Four. Perhaps there are villains who try to stop him from getting to the Elite Four battles. This adds an extra layer of excitement and adventure to the story. Ash would then have to overcome these obstacles while also preparing for the tough battles ahead with the Elite Four.
He might face some tough battles right away. The Elite Four are known for their strong Pokémon and strategic skills. Ash would have to quickly adapt to their level of play.
One possible plotline could be that Jaune has been hiding his Faunus identity to avoid discrimination. As the story progresses, his secret might be revealed during a crucial event, like a battle where his Faunus abilities give him an edge.
One possible plotline could be that Naruto discovers a hidden vampire world while on a mission. Maybe he stumbles upon a vampire lair and has to figure out how to deal with these new, powerful creatures. He could be intrigued by their powers and try to learn from them while also keeping his own ninja village safe from any vampire threats.
One possible plotline could be that Naruto has been hiding his blindness all along to protect his friends. He might have developed special techniques to compensate for his lack of sight, like relying more on his other senses such as smell and hearing. For example, he could use his sense of smell to detect enemies' movements and positions, similar to how he uses it to find Sasuke in the original series. Another idea is that his blindness is a result of some hidden power or curse, and as the story unfolds, he has to find a way to either overcome it or use it to his advantage.
One possible plotline could be that they got engaged during a dangerous adventure. Maybe they were trapped somewhere and made a pact to get engaged if they survived. And then they keep it a secret because they know their friends and families might not approve. For example, Ron might be really shocked and angry at first if he found out.
One possible plotline could be that Ruby discovers her hidden princess heritage and has to balance her normal Huntsman duties with the newfound responsibilities of royalty. Maybe she has to attend grand balls and diplomatic meetings while still trying to fight Grimm. Another could be that she has a secret princess identity that she uses to infiltrate an enemy kingdom or group, using her charm and skills as Ruby as well as her new royal persona.
One possible plotline could be Timmy struggling to keep her secret while dealing with her Fairy Godparents. Maybe she's afraid they'll react differently if they find out she's a girl. For example, she might worry that they'll start treating her like a princess instead of a regular kid with wishes.
One possible plotline could be that they discover they have more in common than they thought. Maybe they start working together on a project in the wizarding world, like researching a long - forgotten magic. As they spend time together, they realize their feelings for each other have changed from hatred to love. To avoid the chaos that would ensue from their families and friends' reactions, they decide to marry secretly. Another idea is that they are forced into a situation where they have to pretend to be married for some magical reason, like protecting a powerful spell or object. During this time, they start to really fall for each other and end up making it a real, secret marriage.