A great plot idea could be a time - travel plot. What if one of the heroes accidentally travels back in time to before they got their powers? They could try to prevent a certain event that led to the creation of a super - villain. Or, perhaps a hero gets sent into a parallel universe where the roles are reversed and the villains are the heroes. This would force them to reevaluate their own beliefs and actions.
One idea could be exploring an alternate universe where Naruto's parents didn't die. This would change his whole upbringing and how he views the world. He might not be as driven to become Hokage in the same way, and his relationships with characters like Iruka and Sasuke could be very different.
Perhaps there's a situation where the heroes of tomorrow are suddenly stripped of their powers. They then have to rely on their wits, training, and teamwork more than ever. They find out that an old enemy from the original Avengers' past has developed a technology that can nullify superpowers. Now they have to figure out how to get their powers back and stop this enemy before it's too late.
One idea could be a crossover with the Naruto universe. The Saiyans could learn about chakra and how to use it, while the ninjas are amazed by the power of ki. Another could be a time - traveling plot where the Dragon Ball Heroes characters end up in the past of their own world and have to prevent a major catastrophe that changes the course of their history. Maybe a crossover with One Piece where they search for the One Piece together and face off against the powerful pirates and the Marines.
Perhaps the heroes assemble to save a powerful magical artifact that is being targeted by a group of dark forces. Each character could bring their own knowledge and abilities to the quest. For example, Hermione's vast knowledge of spells and potions would be crucial, while Harry's courage and experience in facing dark wizards would lead the group. They might also encounter new magical creatures along the way that they have to either befriend or fight.
In this fanfiction, Julius could be a fallen hero who has lost his way. Ishtar, seeing his potential, decides to take him under her wing. She uses her divine powers to help him regain his strength and purpose. As they train together, a relationship blossoms. However, there are those in the heavens who oppose Ishtar's relationship with a mortal, and they try to separate them, leading to a series of adventures and battles as Julius and Ishtar fight to stay together.
One idea could be that the heroes travel back in time to the founding of Camp Half - Blood and have to deal with the very first demigods. They might face challenges like different rules and more primitive living conditions. Another could be going back to a time when the gods were at war with each other more openly and getting caught in the middle of it. Maybe they travel forward in time and see a future where the demigod world has completely changed, like new alliances between different pantheons.
Well, you could write a fanfiction where the Next Avengers: Heroes of Tomorrow have to deal with the public's perception of them. They are young and new, and not everyone trusts them. They could struggle with proving themselves worthy of the Avengers name. Maybe there's a media smear campaign against them, and they have to find a way to clear their names and gain the public's trust. This could involve them doing heroic deeds that are initially misinterpreted, and they have to work hard to set the record straight.
One idea could be Percy having to face a new and powerful monster that is a combination of multiple mythological creatures. This would test his skills and force him to come up with new battle strategies.
A plot idea could also be centered around a mysterious item that has the power to both enhance Yokai abilities and grant the Dimensional Heroes new powers. However, it is being hunted by an evil organization. The heroes and the Yokai Watch crew must protect it. Along the way, they discover the secrets of the item and how it was created, and in the process, they learn more about each other's worlds and grow stronger together.
A cool plot for dc super heroes crossover fanfiction could involve Wonder Woman and Aquaman. Maybe there's a threat that endangers both Themyscira and Atlantis. They must combine their unique skills, like Wonder Woman's combat abilities and Aquaman's control over the sea, to save their respective homes. Also, a Martian Manhunter and Cyborg crossover could be interesting. The Martian Manhunter's shape - shifting and telepathy, along with Cyborg's technological prowess, could be used to stop a cyber - psychic threat.