Well, Naruto might find allies among the outcasts of the new dimension. People who don't fit in with the mainstream society but have unique powers or skills. They could see Naruto as a kindred spirit and join forces with him. Also, if there are any beings in the new dimension that oppose the forces that brought Naruto there, they could be his allies. They might have their own reasons for wanting to help Naruto, like using his power to overthrow a tyrant in their dimension.
In this type of fanfiction, a possible plot is that Naruto is sent to a dimension where time moves differently. He might age at a much faster rate, and he has to quickly master the ways of this dimension to find a way to reverse the time effect on him. Another cool plot could be that he lands in a dimension that is a mirror image of his own, but with opposite personalities for everyone. So he has to deal with a Sasuke who is overly friendly and a Kakashi who is always serious, which makes for a really strange and challenging adventure.
In fanfiction, if Naruto is sent to a different dimension, he might face all kinds of strange new powers and enemies. For example, he could encounter magic that is completely different from chakra. He would have to quickly adapt to survive. Maybe he'd find allies who are also lost in this new dimension and together they'd try to find a way back home while also dealing with the local threats.
Naruto might start by observing. He would watch how things work in the new dimension. For example, if there are new forms of energy, he'd study how people use it. Then he'd try to apply his ninja skills in new ways. Like if there are flying creatures, he could use his shadow clone jutsu to distract them while he figures out a way to either befriend or defeat them.
Naruto could meet alternate versions of his friends or enemies. For example, he might find a version of Sasuke who has a completely different personality or a different set of skills. This would create interesting interactions and potential conflicts or alliances.
A group of rogue ninja from the other dimension could also serve as the main antagonists. They might be jealous of Naruto's power from his original dimension and want to steal it for themselves. They could be led by a charismatic and devious leader who has a personal vendetta against Naruto for some reason, like he believes Naruto will disrupt their way of life in the dimension.
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.
One possible plot twist could be that in the other dimension, Naruto finds out that all his friends have different personalities. For example, Sasuke could be a peaceful scholar instead of a brooding avenger. Another twist might be that the chakra system works completely differently in this new dimension. Maybe instead of using hand signs, they use some kind of mental power to perform jutsus. Also, Naruto could discover that the Akatsuki in this dimension are actually the good guys, fighting against an evil ninja clan that wants to take over the world.
In such a fanfiction, Naruto might use his ninja skills to quickly adapt in the new world. He could make new friends and enemies. His chakra abilities would be a great advantage, perhaps making him a sort of legend in that world.
Ichigo often develops greater adaptability. He has to quickly adjust to the new environment, rules, and powers in the other dimension. This makes him more flexible in his thinking and combat strategies. For example, if the dimension has a different type of energy, he learns to incorporate it into his attacks.