In a fanfiction plot, the Hydra experiment might accidentally create a hybrid of two Avengers' powers. This new entity is confused and out of control, and both Hydra and the Avengers are trying to get it on their side. The Avengers want to help the entity understand and control its powers, while Hydra wants to use it as a weapon. Meanwhile, the original Avengers are also dealing with the moral implications of this new creation.
Well, a possible plot could be that the Hydra experiment was actually a cover - up for a much larger and more sinister plan. The Avengers discover that the experiment was just the tip of the iceberg and they have to race against time to stop Hydra from unleashing something far worse. It could also be interesting if the experiment somehow gives an ordinary person the ability to see into the future, and that person becomes a key figure in the battle between the Avengers and Hydra.
Perhaps in the 'avengers of hydra fanfiction', Hydra has developed a new super - weapon that can neutralize the Avengers' powers one by one. The story could follow the Avengers as they scramble to find a way to counter this weapon while also dealing with Hydra's attacks on various cities. Or, there could be a plot where a powerful Hydra agent uses magic to possess some of the Avengers and make them do Hydra's bidding, and the remaining Avengers have to find a way to break the spell.
Captain America could be the main character. Since he has a long - standing history with Hydra (in the sense of fighting against their evil), he could be the one leading the charge to uncover and stop the Hydra experiment. His strong moral compass would make for an interesting dynamic as he tries to save those affected by the experiment.
One idea could be a character with the Hydra Bloodline having the ability to split into multiple versions of themselves during battles, like the Hydra in mythology. Each split could have a different combat skill, making it a very unique fighting style.
One plot idea could be that Captain Hydra, in a universe where he exists, tries to recruit Tony for his evil plans by appealing to Tony's scientific curiosity with some dark technology. Another could be a scenario where Tony, initially unaware of Captain Hydra's true nature, teams up with him for a project but slowly discovers the truth and has to fight against him. Or perhaps a story where they are both caught in an alternate dimension and must work together, reluctantly in Tony's case, to find a way back home while Captain Hydra keeps trying to undermine Tony's good intentions.
One idea could be that Danny is experimented on by a new group of ghost hunters who want to find a way to permanently strip him of his powers. They use some high - tech equipment that has unforeseen effects on his ghostly half, causing him to have strange new abilities. Another could be an experiment gone wrong in the Ghost Zone that Danny has to deal with the consequences of, like accidentally creating a new type of ghost. Maybe Danny himself decides to conduct an experiment to see if he can control his transformation better, but it backfires and he gets stuck in his ghost form for a while.
Maybe an experiment goes wrong and Peter Parker's spider - sense gets amplified to an extreme level. He has to learn to control it while also dealing with new villains who are attracted to this strange new power. For example, a villain who can manipulate electromagnetic fields that disrupt Peter's amplified spider - sense.
Perhaps Orochimaru's experiment accidentally releases an ancient evil that was sealed long ago. Naruto, being the hero he is, takes it upon himself to reseal the evil. Along the way, he discovers secrets about his own family and the origin of chakra that are linked to Orochimaru's experiment.
One idea could be a crossover where Hydra discovers the wizarding world in the Harry Potter universe and tries to use magic for their evil purposes. The Avengers somehow get wind of this and team up with Harry Potter and his friends to stop Hydra. Maybe they have to battle magical creatures that Hydra has corrupted with dark magic.
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.
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.