Discussion of "himbos" in fandom circles has grown increasingly popular as of late. For those who do not know, a himbo is essentially the male counterpart to the stereotypical "bimbo." Himbos are strong men who are lacking in intelligence but make up for that with their kind-heartedness. They're charming due to their puppy-like earnestness or social awkwardness.
Many anime characters qualify for himbo status, given how long the "idiot hero" trope has existed. The idiot hero is particular common in shonen battle manga. Such protagonists are passionate, sometimes childlike or immature, combatants fiercely loyal to his friends and companions, often falling for tricks and plots because their brains simply don't compute in a way a more cynical mind might.
Goku, the Archetype Idiot Hero
Many of the popular tropes and character archetypes of shonen anime date back to Akira Toriyama's iconic manga Dragon Ball. Dragon Ball starred Son Goku, a character who simply didn't understand the world around him outside of how it related to his passion: fighting. Perhaps the peak of Goku's wacky ignorance was agreeing to marry Chi-Chi as a child because he thought "marriage" was a type of food. As he grew up, Goku matured in many ways but never lost that sense of childlike innocence. Goku remained a silly but sincere character, with his purity of heart being one of the core reasons why he was the first to transform into a Super Saiyan.
To an extent, his son Gohan inhereted some himbo qualities -- but subverting the trope, Gohan is incredibly intelligent. His emotional sincerity and openness, especially with his future girlfriend and wife Videl, match the endearing positive qualities associated with himbos. Also, despite his intelligence, he often misses social cues, so he retains the obliviousness of a himbo. One example of this is when he dresses in the incredibly dorky Great Saiyaman outfit, excited to show it off time and time again despite everyone except for Videl thinking it's ridiculous.
Himbos and Subversions
The idiot hero archetype would diverge from Goku and Gohan into three distinct paths. The first path is the straight-forward himbo hero. These are clueless, fighting-obsessed heroes with a dorky excitement for combat (or their particular obsession) and a lack of knowledge outside their primary area of focus. Characters like Naruto Uzumaki and Monkey D. Luffy fit the bill, as do Promare’s Galo, Fairy Tail’s Natsu and Black Clover’s Asta.
However, as with all popular trends, there are subversions to himbo tropes. Some characters are similarly fighting-obsessed, but also incorporate significant strategy and thought. Yusuke Urameshi and Ichigo Kurasaki from Yu Yu Hakusho and Bleach both fit this mold. Neither are as overtly goofy as Naruto or Asta, but there is a child-like nature to their characters, as well as a fierce loyalty. These characters are not booksmart, but unlike the typical himbo, they're incredibly streetsmart.
Then there's the trend of himbo best friend groups, where supporting characters may share only one brain cell among them. One of the best examples of this is in My Hero Academia, with Kirishima and Kaminari both being kind-hearted goofs who compensate for a lack of knowledge with unabashed, sincere empathy. Bakugo arguably also counts if only for how socially oblivious he is.
It's incredibly uncommon to find a shonen protagonist who doesn't embody at least some himbo traits. Even clearly non-himbo heroes will resemble the archetype in some form; Himura Kenshin, for instance, acts like a himbo as a front, while Kenshiro from Fist of the North Star is beefy enough to look the part but is too all-around hyper-competent to qualify. When you encounter a male lead in a shonen manga who doesn't have any himbo traits, you're probably looking at a villain protagonist like Death Note's Light Yagami.