One interesting Naruto absorb fanfiction could be where Naruto gains the ability to absorb chakra in unique ways, like from nature itself. This could lead to him having new and powerful jutsus.
One interesting concept could be the way a character's body absorbs new powers or abilities. For example, they might absorb the chakra of a powerful enemy and gain unique skills as a result. It can also lead to interesting changes in the character's appearance or personality.
In this fanfiction, the Sharingan from the Uchiha clan is an obvious choice. It has so many abilities like the ability to copy jutsu and predict movements. Naruto could become even more of a prodigy if he absorbs it. Also, the Aburame clan's ability to control bugs could be quite interesting. Naruto could use bugs for reconnaissance or even in combat in ways that are different from his normal fighting style. And the Inuzuka clan's connection with animals, if Naruto could absorb that bloodline, he might be able to form a stronger bond with his summons or other animals in the wild.
He could absorb the Sharingan ability. Imagine Naruto with the power to copy jutsus just like a Uchiha. Another interesting one would be the Byakugan. He could gain enhanced vision and be able to see the chakra points even more clearly. Or perhaps the ability to control sand like Gaara. That would be really cool.
One interesting way is when Naruto absorbs chakra through his shadow clones. In some fanfictions, the clones can be used not just to gather information or attack, but also to absorb the chakra of the opponents they interact with. Then, they transfer this absorbed chakra back to Naruto, making him more powerful.
In some fanfictions, Naruto might absorb Momoshiki through a unique kekkei genkai. For example, if the author creates a new form of chakra manipulation that allows Naruto to assimilate Momoshiki's power during their battle. This could be a result of Naruto's Uzumaki bloodline having some hidden potential that gets unlocked in the heat of the fight.
In fanfiction, Percy could absorb the ability to heal others instantly. This would be a great addition to his existing powers as it would make him not just a fighter but also a healer. Additionally, he could absorb the power to communicate with animals. This would give him an edge in many situations, like getting help from wild animals during a battle or getting information from them about the surrounding area.
In some Naruto fanfictions, Naruto might absorb DNA through special jutsu or abilities. For example, he could have a unique kekkei genkai that allows him to take in and assimilate the genetic material of others. This could potentially give him new powers or abilities related to the DNA he absorbs, like if he absorbs the DNA of a Sharingan user, he might gain some form of Sharingan - like abilities.
In some Naruto fanfictions, Naruto might absorb animals through special jutsus or abilities. For example, he could have a unique kekkei genkai that allows him to take in the essence or chakra of animals. It could also be related to some sort of pact or bond he forms with the animals, which then enables him to absorb their powers.
In some fanfictions, it could be through a special jutsu. Maybe Naruto discovers a long - forgotten jutsu that allows him to merge with his dark counterpart. This jutsu might require a great deal of chakra control and concentration.
One interesting Naruto fanfiction could be those that explore an alternate universe where Naruto becomes a villain. It flips the whole story on its head and shows a different side of the characters. Another type is the ones that focus on Naruto's relationships in a more in - depth way, like his friendship with Sasuke evolving in unexpected ways.