Well, it could be something like a fire - based kekkei genkai that allows Naruto to control blue - flame fire which is hotter than normal fire. This would give him an edge in battles and also a new look to his fighting style.
It could be a water - based kekkei genkai. Since the Wave arc has a lot to do with water, it would make sense for Naruto to awaken a kekkei genkai related to water. This could give him an edge in battles, especially in the Wave region where water is abundant.
One common combination is the Sharingan and the Rasengan. The Sharingan's ability to analyze and predict movements can be really useful when Naruto is forming and launching a Rasengan. Another could be the Byakugan and Sage Mode. With the Byakugan's enhanced vision, he can better sense the chakra flow around him in Sage Mode, making his attacks more precise. Also, sometimes you see him with the Ice Release along with his regular Wind Release. He could then create ice - infused wind attacks that are both cold and sharp.
One popular type of kekkai genkai in Naruto fanfics could be the Sharingan. It gives characters enhanced perception and the ability to copy jutsu. In fanfics, authors might explore new ways to use it or create unique versions. For example, a character could have a Sharingan that can not only see the flow of chakra but also predict an opponent's long - term strategies. Another kekkai genkai is the Byakugan. Fanfic writers could develop stories where a character with Byakugan discovers hidden secrets in the ninja world that others can't. They might use it to find ancient artifacts or lost techniques. The Wood Release is also a great focus. In fanfics, a character with Wood Release might be able to create entire forests that have special properties, like healing those within it or hiding from powerful enemies.
Another aspect could be a fanfiction set in an alternate universe where Genkai and Younger Toguro are allies against a greater evil. They could use their combined skills and knowledge to fight off powerful demons. This would show a different side of their relationship, more of a partnership than what we might expect from their normal interactions in the original series.
Having a kekkei genkai in fanfiction could completely transform Naruto's journey. It might unlock hidden potential within him, affect his relationships with other characters, and introduce new conflicts and resolutions that weren't present in the original storyline.
Another possibility in fanfics is that Naruto could have a Kekkei Genkai that is related to space - time manipulation. This could be inspired by his connection to the Nine - Tails and the fact that he has access to a lot of chakra. With this Kekkei Genkai, he could teleport short distances or even create small pocket dimensions to store items or trap enemies.
In some fanfictions, a side character from the original Naruto series could be made into the main character. For example, Rock Lee. He doesn't have any Kekkei Genkai in the original, but in this fanfiction, he could be given one of the 9 Kekkei Genkai and the story could be about how he overcomes the limitations he had before with his newfound power.
One interesting kekkei genkai in Naruto fanfiction could be the ability to control time on a small scale. This would allow a character to freeze an opponent briefly in battle or speed up their own movements. Another could be the power to manipulate elements in unique ways, like combining fire and water to create a scalding steam attack. And there's also the kekkei genkai of telepathy, which enables a character to read minds and communicate mentally with others, giving them an edge in both combat and strategic planning.