For Naruto in fanfiction, the three bloodlines could be really interesting. He could have the Rinnegan as one bloodline, which would open up a world of powerful and unique abilities like the Six Paths techniques. Another could be the Ice Release bloodline from the Yuki clan, allowing him to control ice in various forms. And finally, the Magnet Release bloodline from the Sand village, which would let him manipulate magnetic forces. These bloodlines would completely change the way he fights and is perceived in the Naruto universe.
Maybe a bloodline that gives him the ability to heal emotional wounds. Since yaoi fanfiction often deals with complex emotional relationships, such a bloodline would be quite interesting. It could be that Naruto uses this ability to help his partner or other characters deal with their past traumas and insecurities, thus strengthening their bond.
He could potentially have a made - up doujutsu bloodline. For example, a doujutsu that allows him to see the future for a short period. This would give him an incredible advantage in battles as he could anticipate his opponents' moves far in advance. Another option could be a doujutsu that lets him manipulate the elements he sees with his vision, like being able to freeze water just by looking at it in a way.
In some fanfictions, one could be the Sharingan, which gives abilities like seeing chakra and predicting moves. Another might be the Byakugan, with its great vision powers. And the third could be something unique like the Ketsuryugan, which could have powers related to blood manipulation.
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 have the Sharingan's ability to copy and predict moves. Also, the Byakugan's near - 360 - degree vision would be really cool. And if he had the Rinnegan, he could use all kinds of powerful jutsu like the Deva Path's gravity manipulation.
One interesting combination could be the Uchiha bloodline with the Uzumaki bloodline. The Sharingan from the Uchiha and the massive chakra reserves and sealing abilities of the Uzumaki could create a really powerful Naruto. Another could be the Hyuga bloodline combined with the Uzumaki. The Byakugan's visual prowess along with the Uzumaki's chakra would give Naruto enhanced perception and more chakra to use for powerful jutsu.
One possible plot could be Naruto suddenly awakening all bloodlines and using them to defeat a new, extremely powerful enemy that threatens the entire ninja world.
One possible plot development could be that Naruto becomes extremely powerful and is able to defeat enemies with ease. The new bloodlines might give him unique abilities like enhanced speed, strength, and elemental control. He could also face challenges as others might fear his newfound power.
Well, if Naruto has three bloodlines in fanfiction, it could greatly enhance his abilities from the start. For example, one bloodline might give him enhanced physical strength, another could provide unique ninjutsu capabilities, and the third might offer some sort of special perception. This would likely make him more confident earlier on as he wouldn't have to struggle as much with basic power levels. It could also lead to him being more isolated as others might fear or envy his multiple powers.
Maybe he uses some kind of special jutsu. It could be a new form of his shadow clone jutsu where the clones are able to analyze and then copy the bloodline traits of the opponents they encounter.