A great plot could be that there is a rift in the multiverse. The Naruto universe and the Marvel universe start to merge. The Avengers and Naruto's team both see their worlds being threatened. Characters like Captain America and Naruto would bond over their strong sense of justice. They would face challenges like dealing with the different power systems. For example, the Hulk's brute strength compared to the finesse of ninja techniques. But in the end, they find a way to use their combined powers to close the rift and save both universes.
One possible plot could be that the Avengers are somehow transported to the Naruto universe. They team up with Naruto and his friends to fight a common enemy like Kaguya who has somehow obtained the Infinity Stones. The Avengers' powers and technology would be a huge shock to the Naruto world, and they'd have to learn to combine their skills to succeed.
One possible plot could be that Naruto is somehow transported to the Marvel universe. The Avengers initially mistake him for a threat. But Naruto, being Naruto, tries to explain his situation. He then shows them his ninja skills like shadow clones and Rasengan. Together, they could face a common enemy like Thanos, who has acquired some sort of ninja - like powers. Naruto's ability to never give up and his strong will could inspire the Avengers, and his combat skills could be a great addition to their team in the fight.
Well, a great plot could be that the Infinity Stones start to mess with the fabric of reality and it creates a portal between the Naruto universe and the Marvel universe. The Avengers and Naruto's friends end up in each other's worlds. Naruto and the Avengers have to work together to fix the portals and return everyone to their proper universes. Along the way, Naruto might have some epic battles with villains like Loki, using his ninja speed and strength. And the Avengers could learn a thing or two about chakra from Naruto and his friends.
A cool plot might be that the Tailed Beasts in the Naruto world are being targeted by an unknown force from the Marvel universe. The Avengers, thinking it could lead to a greater threat to both universes, come to help. Naruto and the Avengers have to work together to protect the Tailed Beasts. Hulk could have an interesting interaction with the Tailed Beasts, perhaps learning from them how to better control his rage, while the ninjas are amazed by Thor's lightning powers and try to incorporate some of that into their own jutsu.
Well, perhaps there's a threat that can only be defeated by combining the chakra in the Naruto world with the superpowers of the Avengers. For example, Thor's lightning could combine with Sasuke's lightning - based attacks. And Captain America's leadership could inspire Naruto to lead his own team in a new way. They all start off not trusting each other much, but as they face challenges together, they learn to work as one.
One possible plot could be that a powerful villain from another dimension threatens both the DC and Marvel universes. Superman and the Avengers have to put aside their differences and combine their powers. For example, Superman's super strength and flight could be paired with Thor's godly abilities and Captain America's leadership. They could start off not trusting each other, but as the battle progresses, they learn to work together and defeat the villain in an epic showdown.
A cool plot could be that a villain creates a device that can manipulate time. This device causes chaos as it starts to merge different timelines. Spider - Man gets caught in the middle of this temporal mess while on a normal patrol in New York. He then reaches out to the Avengers for help. The Avengers, who have experience with time - related issues from previous adventures, team up with Spider - Man. Thor uses his lightning to disrupt the device's power source, while Spider - Man swings in to physically disable it with the help of Black Widow's combat skills. In the end, they manage to restore the timelines and save the day.
One possible plot could be that a powerful new villain emerges that threatens both the Marvel Universe and Wonder Woman's world. The Avengers and Wonder Woman cross paths while investigating the strange occurrences related to this villain. They initially have some clashes due to their different methods and cultures, but then realize they need to work together. For example, Iron Man might be impressed with Wonder Woman's indestructible bracelets and try to analyze them, while Wonder Woman could learn about modern technology from Stark. Eventually, they combine their powers and skills to defeat the villain.
Another idea is that a villain creates a rift between the two universes. The Avengers and Merlin have to team up to close this rift. During their journey, they exchange skills and knowledge. Black Widow could teach Merlin some combat skills, while Merlin could show the Avengers how to use magic in a more strategic way. This way, they not only close the rift but also become stronger as a combined force.
One possible plot could be that the Avengers are somehow transported to the Arrow's universe. Maybe a villain in the Arrowverse has acquired a powerful artifact that creates portals, accidentally pulling in the Avengers. Then, they team up with Arrow and his team to fight against a common enemy, like a new super - powered threat that neither group could handle alone.
One possible plot could be that Batman's Gotham is threatened by a powerful villain who has some connection to the Avengers' universe. Maybe Loki decides to cause chaos in Gotham as part of a larger plan against Earth. Batman, being the detective he is, starts to investigate and soon realizes that this is no ordinary criminal. He then somehow gets in touch with the Avengers, perhaps through SHIELD's intelligence network. Together, they combine their skills and resources to take on Loki and his minions. Batman's stealth and strategic mind would complement the Avengers' superpowers.