Maybe Naruto uses his Sage Mode to sense their danger and arrives just in time to save them. He then offers them a chance at a new life.
One possible scenario in this fanfiction could be that Naruto discovers Haku and Kimimaro in a dire situation. Haku, with his ice techniques, and Kimimaro, with his powerful bone abilities, are perhaps being overpowered. Naruto, being the hero he is, jumps into the fray. He may convince them to change their ways and join him in Konoha, as he once did with Sasuke. This would not only show Naruto's growth as a ninja but also his ability to bring out the best in others.
Well, in a 'naruto meets haku fanfiction', Naruto could be on a mission and suddenly come across Haku in a strange, mystical place. Haku could be there to give Naruto some sort of warning or guidance. They might then team up briefly to face a new threat that is related to the secrets of Haku's clan. Naruto would be eager to learn more about Haku's past and powers, and Haku would see how much Naruto has grown as a ninja.
In the fanfiction, Yugao might be in the middle of a battle she can't win. Naruto arrives on the scene, his presence alone giving her hope. He then uses his various jutsus like the Summoning Jutsu to call for backup or his Sage Mode to overpower the opponents. Saving Yugao could also be a turning point in Naruto's story, leading him to discover new powers or gain new respect from the other ninjas in the village.
In a 'naruto saves boruto fanfiction', Naruto might use his powerful jutsu like Rasengan to fend off enemies threatening Boruto. He could also use his experience and wisdom to guide Boruto out of a difficult situation, perhaps one involving a powerful new villain in the ninja world.
In the fanfiction, Sarutobi could be kidnapped by a group of ninjas from another village. Naruto would then embark on a solo mission to rescue him. He'd use his stealth skills and knowledge of the terrain to infiltrate the enemy's hideout and save Sarutobi without being detected.
It could also result in a change in the way the village views their relationship. Since Naruto is a hero, his saving of Hinata would be a big deal. This could lead to the village elders or the people in general being more accepting of a possible romantic relationship between them. For example, they might start to see Hinata as a more important figure in Naruto's life and give her more respect.
Well, Naruto could save a woman who is trapped in a collapsing building during an enemy attack. He could use his super strength and speed to get her out safely. Then, the woman might be so grateful that she offers to help Naruto in his future missions in some way, like providing him with valuable information about the enemies.
In a 'Goku Saves Naruto' fanfiction, Goku might teach Naruto some of his unique fighting techniques. Since Goku has such a vast knowledge of martial arts and energy control, he could help Naruto become even stronger. For example, he could show Naruto how to better control his chakra using the principles of ki control. And also, Goku's fearless attitude in battle could inspire Naruto to face his enemies more bravely. Goku could also use his Dragon Balls to wish for something that would benefit Naruto or his village, like restoring the damage done by a powerful enemy attack.
Perhaps Naruto teams up with Shikamaru. Since Shikamaru was very close to Asuma, they could combine their skills. Naruto's brute strength and Shikamaru's intelligence would make a great duo. They could come up with a complex plan to save Asuma from whatever danger he is in, like a deadly curse or a powerful enemy's attack.
Well, Naruto could use his Nine - Tails chakra to create a powerful shield around Mikasa when the Titans are attacking. This would protect her from their attacks. Then he could use his chakra arms to grab onto nearby buildings and swing them both to safety.