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.
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.
An interesting plot could involve an OC who has the power to communicate with animals. In the story, they use this power to gather intel on the villains' plans. The animals could provide information that the Avengers wouldn't be able to get otherwise, like the location of a hidden lair or the movements of enemy troops.
It could involve the next - generation heroes facing a new and powerful villain that the original Avengers couldn't defeat. Maybe they have to use new powers or technology.
In the 'The Next Avengers: Heroes of Tomorrow Fanfiction', it could also be about the relationships between the new Avengers. They come from different backgrounds and have different personalities. There could be some internal conflicts at first. But as they face challenges together, they learn to work as a team. Maybe there is a love story between two of the young heroes that develops as they fight side by side, which also adds an interesting element to the overall story.
A cool plot for My Hero Academia Heroes of Tomorrow fanfiction could be that there's a quirk - based disease that starts affecting heroes and students. The main characters then have to find a cure while still maintaining order in the hero society. Also, a plot where the heroes are transported to a parallel universe where the roles of heroes and villains are reversed could be really interesting. They would have to figure out how to get back while also dealing with this new and strange world.
A really cool plot idea could be that the Avengers are watching Endgame in a sort of 'alternate reality cinema' where the events in the movie start to bleed into their real world. So they have to stop the movie from fully playing out to prevent chaos in their own universe. This would involve a lot of action and strategic thinking as they try to stop things like Thanos from emerging from the screen while also trying to understand the significance of what they're seeing in the movie.
A possible plot is that a powerful enemy from the future in the Legends of Tomorrow timeline discovers the power of chakra in the Naruto universe. So, they travel back in time to try and harness it for their own evil purposes. The Naruto characters, along with the Legends of Tomorrow crew, must then join forces to stop this enemy. This would involve the Legends of Tomorrow team learning about ninjutsu and the Naruto characters learning about time - travel technology.
One idea could be that the mutants and the Avengers have to team up against a common enemy that is immune to their individual powers. So they must learn to combine their abilities in new ways. For example, Wolverine's healing factor could be used to keep an injured Avenger alive during a long battle while Iron Man figures out a way to defeat the enemy.
One idea could be that Harry Potter is magically transported to the Avengers' universe. He could use his magic to help the Avengers in battles, like creating protective shields with spells. Another idea is that the Avengers are somehow sent to Hogwarts, and they have to learn about magic while also dealing with threats in the wizarding world. For example, Iron Man might try to figure out how to integrate his technology with magic.
One idea could be exploring the family dynamics when the Avengers have to take care of a young superhero in training. It would be fun to see how they each contribute to the kid's growth, like Tony Stark teaching about technology and Captain America instilling values.