One idea could be Naruto being transported to a dimension where chakra doesn't exist, but he discovers a new form of energy and has to learn to use it from scratch. This would force him to adapt his fighting style completely.
Maybe in the other dimension, all the ninja clans have different abilities and Naruto has to form alliances with new and strange characters to face a common enemy. For example, a clan that can control time in small increments, and Naruto has to figure out how to use this to his advantage in battle.
Another plot could be that Naruto arrives in a dimension where everyone is the opposite of what they are in his own world. His friends are enemies and his enemies are friends. He has to navigate this complex situation and try to find a way to bring peace to this topsy - turvy world. He might also discover the reasons behind this strange transformation and try to reverse it.
One idea could be that Peter discovers he has special powers in this other dimension that he doesn't have in his own world. For example, he can control elements like fire or water. Another could be that he meets alternate versions of his friends and family, and has to deal with the differences in their personalities. Maybe in this dimension, his best friend is his enemy.
In an 'Avengers Another Dimension Fanfiction', a cool plot might involve a dimension where technology and magic are one and the same. So Iron Man's suit could be powered by both arc reactor energy and some sort of magic spell. Or a dimension where the Avengers are part of a gladiator - like arena, and they have to fight not only their usual foes but also other heroes from different universes just to survive and find a way back home.
Well, a cool plot for 'Harry Potter in Another Dimension' fanfic could be that Harry discovers he has a twin in this other dimension. His twin has been raised by Voldemort and has a very different view of the wizarding world. Harry has to find a way to convince his twin to abandon Voldemort's ways. Or, what if in this dimension, the Sorting Hat can talk out loud all the time and gives very different sorting decisions? For example, it might put all the brave students in Slytherin and the cunning ones in Gryffindor. It would be really interesting to explore how the relationships between the houses change.
Another plot could be that Ichigo is transported to a dimension that is a post - apocalyptic world. Here, his skills as a fighter would be put to the test. He might find remnants of a once - great civilization that had technology far different from his own, and he has to use both his swordsmanship and his wits to navigate this dangerous new world.
One idea could be Naruto getting trapped in a dimension where chakra doesn't exist, and he has to learn new forms of power. Another could be a dimension where the Akatsuki are the heroes, and Naruto has to figure out how to co - exist or change that world. Or perhaps a dimension where all the dead characters are alive again, but in different roles, like Itachi as a rogue ninja fighting against Konoha.
One idea could be Naruto traveling to a dimension where all the villains have become heroes. He has to adapt to this new world order and figure out how to get back to his own dimension.
One interesting plot could be Naruto traveling to a dimension where the Akatsuki are the heroes. It would be a complete role - reversal, and Naruto would have to figure out how to interact with them. Another could be a dimension where everyone has a different type of chakra, like water - based chakra for all shinobi, and Naruto has to adapt his skills.
Another plot could involve a dimension where the Fairy Tail guild has an evil counterpart. Our heroes have to team up with the good versions of their doppelgangers in that dimension to defeat the common evil. They might face challenges in trusting these new allies who look just like their enemies back home.
One idea could be that the main character accidentally activates a forbidden jutsu that transports them to different dimensions in the Naruto universe. For example, they might end up in a dimension where the Akatsuki has successfully captured all the tailed beasts and rule the world. They then have to find a way to team up with some of the remaining shinobi to reverse the situation.
One idea could be that Naruto travels to a dimension where all the female characters from different Naruto arcs are united. They all fall for his unique charm and his skills as a ninja. He has to balance his new relationships while also finding a way back to his own dimension.