For someone that believed he started out without love or friendship, and was honestly hard to get along with as a child, Naruto grew into someone worth forming powerful bonds with. He may not have had it easy, but the friendships he built along the way are what make him the symbol of peace he is in Boruto: Naruto Next Generations.
This list excludes characters like Jiraiya and Iruka due to their bond with Naruto being more paternal in nature, and Hinata, who's feelings for Naruto were always romantic. That's not to say they weren't/aren't important to Naruto's character growth, or that they aren't significant bonds, but that they're not Naruto's friends. If anything, they're his family.
There are spoilers for both Naruto and Boruto ahead, so readers should proceed with caution.
11 Rock Lee
Rock Lee first meets Naruto during the Chunin Exam arc in Naruto, and the two get off on the wrong foot, not unlike many on this list. Rock Lee's explosive taijutsu takes Naruto by surprise, and he ends up unconscious while Rock Lee fights Sasuke.
However, as the two get to know each other they realize that they have a lot in common when it comes to their values, and they develop a mutual respect for one another. One memorable moment is when Rock comes to Naruto's aid despite being just released from the hospital during the Sasuke Retrieval arc to fight Kimimaro. Though they aren't as close as some of Naruto's other friends, Rock Lee and Naruto are kindred spirits, and Naruto learns a lot from Rock's work ethic.
10 Sai
When Sai first joins team seven, Naruto dislikes him quite a bit. He can't stand Sai replacing Sasuke, and he lets Sai's personality get to him more often than not. Yet, when Sai changes his ways and chooses to defend team seven from a surprise attack by Kabuto, Naruto starts to see Sai as a comrade.
Eventually, the two get along well, and Sai visits Naruto during his big training arc in Naruto Shippuden. Sai learns a lot from Naruto about the importance of the bonds of friendship and repays him by being a good, supportive friend through to adulthood.
9 Teuchi
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Teuchi is the owner of Ichiraku Ramen, Naruto's favorite restaurant and the place he has been going to since he was a child. Teuchi might not be a regular character in the franchise, or play a large role in the grand scheme of things, but every time Naruto needs a break from training or comes back from a mission, Teuchi is there for him.
Starting as one of the few comforts Naruto had as a child, Teuchi fed Naruto and treated him as a regular person, unlike many in Konoha at the time. By the time Naruto is an adult, he gets free ramen for life.
7 Killer Bee
Killer Bee is the first jinchuriki that Naruto meets that has a positive connection with their tailed beast. This is a major boon for Naruto as his tailed beast has been giving him a hard time since childhood. In meeting and training with Killer Bee, Naruto learns about himself and his capacity for power in a way unlike any he'd previously experienced.
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Together, Naruto and Killer Bee make an epic duo that has fun together, trains hard, and has deep empathy for one another. Killer Bee might be a lot older than Naruto, but they realize that the experience of a jinchuriki transcends age, making them great friends.
6 Gaara
When Naruto first meets Gaara he is in a very dark place. Gaara is burdened with the One Tail's power, and the curse of being a jinchuriki weighs on him more than most. Throughout the Chunin Exams arc and Orochimaru's assault on the Hidden Leaf, Naruto shows Gaara that he's not alone in his struggle. This creates a strong bond between the two of them, and they become unlikely friends.
Gaara is one of the first people who was deeply affected by Naruto's determination and love. Because of this, the two continuously root for each other and help each other throughout the franchise. Not only are they friends and allies, but they hold a deep respect for each other that pushes the two forward in battle and life.
5 Sasuke
While Sasuke is arguably Naruto's best friend, he spends so much of the franchise as an antagonist that it's hard to rank him as number one. As stated by Naruto, Sasuke is the first person to see him and acknowledge him, making Naruto devoted to saving Sasuke from his revenge plot and the darkness that comes with it.
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Truthfully, Sasuke is a bad friend who hurts Naruto both physically and emotionally countless times. That being said, when Sasuke eventually comes back to the Leaf, he is loyal to Naruto and helps him protect the Leaf from future harm. He atones for his betrayal throughout the end of Naruto Shippuden and Boruto, making him qualify for a higher ranking.
4 Konohamaru
Konohamaru is one of Naruto's first fans. They meet in the second episode of Naruto and become fast friends. Konohamaru idolizes Naruto and Naruto teaches him different jutsus throughout the series. Although the two start more like younger and older siblings to one another, as they grow up they become friends with immense loyalty to one another.
By the time they are adults, Konohamaru is Boruto's sensei and a close family friend to the Uzumaki's.
3 Shikamaru
Although Shikamaru started off with the perspective that Naruto was nothing but a troublemaker, his view quickly shifted as he saw Naruto's progress once they graduated from the ninja academy. By the Chunin Exams arc, Shikamaru started to see something in Naruto that his peers couldn't yet see. By the Sasuke Retrieval arc, Shikamaru was willing to rely on Naruto to fight the strongest foe, but their friendship didn't bloom until the end of Naruto Shippuden and the beginning of Boruto.
In Boruto: Naruto Next Generations Shikamaru plays the role of Naruto's right-hand-man and top strategist while Sasuke does work away from Konoha. Naruto relies on Shikamaru for work and emotional support during his time as the Hokage, in turn, becoming closer than ever.
2 Sakura
Sakura and Naruto's relationship hasn't always been strictly platonic on Naruto's end, as Naruto had big feelings for her throughout much of the franchise. However, Naruto knew about her feelings for Sasuke and honored them until he moved on to loving Hinata. Sakura knew about Naruto's crush and rarely used it to her advantage, almost always keeping things friendly between the two of them.
Around a third of the way through Naruto Shippuden, Sakura went from being a teammate and comrade to being an excellent friend to Naruto. The two shared their pain over Sasuke's betrayal, Sakura supported Naruto during his training and defended him from those that still thought of him as good for nothing.
1 Kurama
Through thick and thing, Kurama was Naruto's best friend. The two shared a bond only understood by those jinchuriki and tailed beasts lucky enough to connect with each other the way Killer Bee connected with his tailed beast and Naruto connected with Kurama. They were war buddies, friends, and each other's biggest confidants.
Although Kurama starts off as an antagonist to Naruto, when they become allies, their bond is immensely strong, with Naruto talking to Kurama in his head. Kurama is physically and emotionally stronger when he's with Naruto, and Naruto is physically and emotionally stronger when he's with Kurama. Together they are unstoppable.