Kouji Kabuto from Mazinger Z pulled this sometimes, specially late in the series (the episode where Erika showed up comes to mind). Dr. Hell also pulled this at the end of Mazinkaiser for seemingly no reason, and despite being a very old man.
Dante of the animatedDevil May Cry series gets this too every so often, but the first example is in the first episode — at the end, Dante comes out of the back wearing nothing but pants, toweling his hair off and dripping water. The fangirls rejoiced.
Yu-Gi-Oh! GX: A favorite coveted screenshot among fangirls is of Kaiser waist up in the shower. Jaden too has a pretty nice body for someone who just plays with trading cards all day.
Yu-Gi-Oh!: Malik Ishtar has several scenes where he strips off his shirt in front of everyone (though it's actually a plot point — he's showing the tattoo on his back), prime material for his fangirls.
Shaman King villain Hao wears a poncho but he is shirtless.
Faust goes through his introductory fight mostly shirtless, but bar certain demographics, it's much more Squick.
Hilariously parodied in the OP for the Sega Saturn game, where the first thing that Akio and Touga do is to open their shirts and show off their chests, much to Saionji's embarrassment.
Major Armstrong from Fullmetal Alchemist enjoys randomly taking off his shirt to show his magnificent musculature. He's so diesel, he could fuel a semi for a trip across mainland China. He does it so often and suddenly, to everyone else's dismay, he's a definite parody of this trope.
Then there's Armstrong's dear friend, Sig Curtis, who's able to rip apart his entire upper wardrobe by flexing. Armstrong and Sig thus become good comrades by the friendship forged with muscle.
Even lampshaded in his fight with Scar.
Edward too has had his share of scenes showing off his torso (and automail arm), beginning with the first chapter.
And Roy Mustang also showed his abs for a particularly dramatic comeback after being thought dead.
Ling had a shirtless dramatic entrance (popping out of a manhole).
Ed even gets an outdoor shower scene in the 2003 anime version, and a majority of his concept artwork shows him pulling or ripping his top off in some fashion.
Alphonse gets a shirtless scene in the fan game Bluebird's Illusion. Ed "accidentally" walks in on him showering.
In the original, the second iteration of Endless Eight has Kyon shirtless at the beginning. It's the Fanservice Episode of Season 2!
Itsuki himself also gets some... attention in the same arc. Mostly of a different kind, considering he was wearing some sort of skimpy black speedo.
Ouran High School Host Club gives all the male characters in the club plenty of opportunities to take their shirts off. The club's website once featured a picture of Haruhi shirtless which, naturally, turned out to be photoshopped.
In a hilarious example, Ranka Lee from Macross Frontier bumps into Alto for the first time (who was shirtless at the moment), and immediately focuses on his face instead, mistaking him for a very beautiful girl.
YuYu Hakusho: Almost all of the main characters (and many of the Big Bads) have multiple scenes in which his shirt is ripped up in the midst of battle. Well, except the bishonen (Kurama) with the largest fan club.
Pretty much the entire male cast of Gintama and one female, though she's hiding it, go shirtless in its 7th ending theme. A subversion exists in the same ending as Prince Hata, who looks much like Dragon Ball Z's fat Buu, not only appears shirtless, but is wearing only a fundoshi.
Hosaka in Minami-ke is prone to going shirtless for little reason or provocation. There's even an eyecatch of him in one of his shirtless moments.
Both Setsuna and Allelujah in the second ED of Gundam 00.
Whether it be a result of the massive Clothing Damage that afflicts the men of Dragon Ball Z ,good old fashioned shower/bath scenes, shirtless training, when someone gets serious, or the odd homoerotic nude visualization of a deceased comrade speaking from beyond the grave, the ratio of shirtless scenes to scenes in which any given male character wears a shirt are around 50-50. (maybe if Videl and Android 18 channeled their ki/energy into their bodies instead of making their clothing Nigh Invulnerable, they would be able to hang with the guys in combat?)
18 had Clothing Damage at one point early on, too — just not enough to reveal anything.
And yet, to the dismay of fangirls everywhere, never once did Future Trunks go without. I think this may be the first instance of a vagooblock in anime.
Occurs twice in the second anime season of Slayers; the first when Gourry and Zelgadis are healing from an attack from a pair of demons raiding Princess Amelia's castle, and the second when said pair's covers are blown during the Once a Seasoncross-dressing episode.It turns out that the Lady Land kingdom they had infiltrated (hence the disguises) is full of men that had also hidden their genders, and increased the shirtless count, including the princess Zelgadis had been falling for. Ouch. Gourry is also seen shirtless in an early scene of the Slayers Premium movie.
A very humorous promotional spread for the Un-Cancelled fourth season, illustrated by the man who drew the illustrations in the light novels, has Gourry and Zel as this again, this time in flimsy swimwear. Xellos and Wizer Freion are in on it also.
Almost as soon as he shows up on screen for the first time in episode 24 of Neon Genesis Evangelion, Kaworu Nagisa ends up stripped butt-naked along with Shinji Ikari in a shower scene. He was only around for one episode so he had to make up for lost time somehow, right?
Rebuild took this even further: until he donned his plugsuit for the first time when Zeruel was attacking, he was a Walking Shirtless Scene. In fact, only one of them qualifies for this trope since in the other, he's completely naked.
Abel Nightroad of Trinity Blood certainly gets his share of shirtlessness. Also, Brother Petros spends the entire fifth volume of the manga without a shirt. And is he ripped!
Hugue has also been sans shirt more than once, revealing a LOT of scars (said scars haven't deterred the fangirls in the slightest).
Abel: I think that... Tres... you are so HOT! Tres: I don't understand what you mean.
Bleach: Most males have a well sculpted chest that will be revealed when his shirt is removed. It's easier to list the male characters who never get a shirtless scene.
Mayuri Kurotsuchi, the squicky Mad Scientist actually gets a shirtless scene. Complete with scars.
Yamamoto Genryusai Shigekuni, the general of the Gotei 13, invariably strips to the waist before using his shikai. For dramatic purpose this reveals an ungodly amount of scars, plus a more muscular figure than the protagonist has, despite being older than the latter's country of origin. In the third movie, he literally jumps out of his shirt before delivering an attack.
Ichigo gets to have shirtless and even almost naked moments, due to Clothing Damage.
Zaraki gets to show off his chest when he gives Ichigo one free attack before they fight. He's also stripped to the waist in the Hueco Mundo arc after fighting Nnoitra. He also shows up shirtless when he shows up to help fight Yammy.
Chad also gets the less fleshy version most of time, but given that he's the embodiment of the Latino stereotype... Yeah.
Even Uryuu has a couple of shirtless scenes, one when his father saves his life from arrancar attacks, and one when his father restores his powers. He's pale, but somehow remarkably well-built. (He's an archer, after all.)
Ulquiorra gets a few shirtless scenes as well. Apparently the fangirls were not disappointed.
In an omake, a few members of the Shinigami Women's Association went to great lengths to get one of these out of Ukitake. Yay!
Subverted in Trigun. Vash the Stampede is fairly good looking in his Badass Longcoat, but when he gets his first shirtless scene, it turns out he's so cut up, scarred, and shot to pieces that he looks like Frankenstein's monster underneath.
And of course Kamina is shirtless all the time. So often that the presence of a shirt-wearing Kamina in Simon's Lotus Eater Dream immediately indicates that some weird shit is going on.
Let's not forget the bath episode, with everyone staying naked for a good 6 or 7 minutes, leading Viral to call the gang "naked monkeys" for the first half the series.
Chrono Crusade has several moments, although most notable is probably the fact that Joshua almost never keeps his shirt fully buttoned (basically only when someone forces him to so he'll be presentable), and Chrono in his true form only wears a jacket that does not cover his chest.
We get several shirtless scenes for Fakir in Princess Tutu; somewhat justified because he has a plot-relevant birthmark on his chest, but also usually with an obvious fanservice factor as well. Mytho also has one scene where he has his uniform shirt unbuttoned in the second season — a tip-off that something is very odd, because normally he wears the shirt fully buttoned... but without pants.
Seiya also manage to get a few, the first one against the before mentioned saint, and another were he takes off his shirt before fighting three Silver Saints and after sneaking out of the hospital.
Deathmask of Cancer also fights shirtless against Shiryu. As does Krishna of Krisaor during the Poseidon arc, and Okko of Tiger before the Sanctuary arc. The Dragon Saint tend to have that effect on his opponents.
Happens surprisingly often in One Piece with the most prominent example being Ace, where practically every scene he's in turns into a shirtless scene. Also happens with mostly with Luffy, Zoro and Franky. A notable example for Zoro occurred during the Drum Island arc, where he spends a good portion of the crew's time there wandering around without a shirt on.
Parodied when a woman's baby messes Zoro's shirt, so the mother yanks it off to clean it for him. Before she explains why she stole it, he angrily accuses her of being a pervert.
After the timeskip, Zoro signifies that he's getting serious by stripping off his coat in addition to donning his bandanna.
During Tsukune's fight with Moka's father near the end of Rosario + Vampire Capu2, he gets his shirt blown apart when the residual vampire blood in his body starts working again.
This happens a few times in the second season of the manga, mostly in the Sun arc but he is first shirtless on the frontpage on the 18th chapter probably just to show how badass he has become and well it worked
Naruto spends a good few chapters shirtless and covered in oil in Naruto Shippuuden. Sasuke has a brief shot in a movie trailer drenching himself under a waterfall. It was rumored that the fangirls could be heard for miles around.
Hidan, after a fight, has his Akatsuki uniform half ripped up, making all his appearances later on be half-Shirtless Scenes. Apparently Kakuzu was too much of a tightwad to give Hidan money to get another one.
Not just Hidan. Deidara, Sasori, Kakuzu and Pain go shirtless at one point in time as well.
Itachi, who is the most normal Akatsuki member in terms of appearance and abilities is the only member in Akatsuki that dies without being shirtless. He loses his cloak while fighting Sasuke but under it is a shirt.
Then we got shirtless Danzo (who was also bleeding profusely and had his arm reduced to a stump at the time), which could not be more Fan Disservice.
In some anime only scenes and a filler episode, we get to see Jiraiya in the hotspring with his chest completely bare. We also get to see this in the manga, but by that point, he has a huge scar obscuring most of chest.
Also, people tend to forget this, but Gaara's older brother Kankuro also had a shirtless scene in episodes 11 and 12 of Naruto Shippuden as well as the manga. After he was poisoned by Sasori, he was immediately rushed to a hospital room where he is shown topless as well as not having his hood and face-paint on. He was shown to be very well-built and toned (and he even gained some fangirls as a result!)
Pokémon Special required Red to use his shirt to tie down a steering column on an airship while he went to defuse one of Carr's Forretress bombs. Since he cast off his jacket prior to his battle with Giovanni, this trope is the result of these desperate measures.
And he manages to stay that way for over half a saga.
Several Digimon across all of the Digimon shows (and games) have humanoid bodies, and are usually, if not always, shirtless. Weregarurumon and Leomon are prime examples. Now, if only they'd get more screen time, and Leomon would stop dying!
In a less Furry Fandom example, in Digimon Savers, there are a few male gratuitous shower scenes (but not angsty) as well, from both male main characters. It was known by some as Digimon Fanservicers due to this.
Yes, there was a naked Furo Scene involving all four of them. The fangirls peeping in on them didn't stand a chance.
Many of the characters in Eyeshield 21 have shirtless scenes after practices and times like that. Mizumachi just likes stripping down to his shorts and waving his shirt around (he used to be a swimmer, which might explain it). Ootawara on the other hand turns it into Fan Disservice by often losing his pants (and sometimes everything else) and farting a lot.
Mahou Sensei Negima! occasionally gives Negi shirtless scenes. It's less Squicky than one would expect, as he's usually magically aged into a teenager when they happen.
Like, for example, teenage Negi vs. Jack Rakan in a shirtless battle worthy of the Tenkaichi Budokai.
One episode of Soul Eater featured Soul trying to cheat on a test by hiding cheat sheets in his clothes, and then being strip-searched by the teacher when he caught him. Soul spent the rest of the test in only his boxers, much to the glee of the fangirls.
Also, Black☆Star. Besides having awesome biceps he's also BUFF when you see him shirtless with just a towel over his shoulders after training.
In perhaps the most gratuitous example, Free is shirtless for his illusionary fight with Death the Kid. He's wearing a shirt in the scene immediately before and puts it back on immediately after, and there's no obvious reason why he took it off just to fight. (By the way, he's in his Wolf Man form most of the time, which may detract from or enhance the effect, depending on your preferences.)
In the manga only, Ox, Harvar, Kilik, and the pots hang around the school shirtless after coming back from an extremely Hot-Blooded mission.
In addition, the dust jackets of the manga include pictures of the cast in skimpy bathing suits. Not wanting to isolate the female audience, these bits of fanservice include Kurz◊ and SÃ'suke◊
Kalinin in the anime, after being wounded during the Behemoth arc. Complete with bandages.
Gauron, of all people, in the manga. Not that the anime gave you a different idea, what with how well that uniform fit him, but in the manga he looks as if he was chiseled in stone.
Ryo from Ronin Warriors goes shirtless for a good two or three minutes at the beginning of episode 20, after he awakens from a Catapult Nightmare.
Until a significant way in Tsuna from Katekyo Hitman Reborn! ripped his shirt and pants off every time he activated his attack, leaving him in just his boxers while he fought. Also, near the beginning of the TYL arc, both him and Gokudera are shirtless in the middle of a forest at night. Brrr.
During his battle with Belphegor, Gokudera wore his shirt completely unbuttoned and hanging open with nothing covering his torso save for a lot of bandages.
Ryohei is embodiment of this trope, 'cause he gets more Shirtless Scenes than any other character. And he's quite hot.
And don't forget about the latest Katekyo Hitman Reborn OAV where we get a veryyy veryyy looong extra bonus screentime focused on Hibari Kyoya's chest in an Onsen. The day it was released, many fangirls died from bloodloss.
Few fans of Darker Than Black will forget November 11's Naked First Impression with Mao, and not just because it was funny. Hei's civilian alias Li on the other hand is a textbook case of the "partially buttoned shirt" variant, as he seems physically incapable of having more than three buttons done at any given time. No wonder every woman in sight falls for him.
Li's partially unbuttoned shirt is Lampshaded in the OVA (and was then immortalized as a Memetic Mutation) in the form of two in-universe women fixating on his collarbone, which is often noticeably visible because of this trope.
Actually, if you look carefully at that scene, her clothes were stuck to the barbs of the monster. Ripping them off was clearly the only option. Her dialogue after the battle does show that she took the term "Topless" literally, though, by claiming that she had become one.
England from Axis Powers Hetalia gets one when he takes a hot bath in Japan's house. The scene was amped up for Fanservice effects in the anime rendition, adding a bit of Ship Tease when his host is nonplussed at his nudity — yes, the same guy who was scandalized when his partners paraded around without shirts. Germany has a pretty hot Shower Scene in the Manga also.
When Yume from Somedays Dreamers meets her magic instructor Masami for the first time, he is completely shirtless, leading to a very flustered reaction for the poor girl. Of course, that Masami's best friend Kera opened the door being practically shirtless as well doesn't help matters.
There's another Fan Disservice example at the end of the second arc when Battler briefly gives up. Beatrice chains him up and parades him around naked.
In The Violinist of Hamelin, everytime Hamel transforms into a Mazoku he bursts out of his clothes. In the anime, his signature black outfit even seems to somehow grow back everytime he changes back. In the manga, Drum attacked the human army with giant spikes that shot out of the ground... and somehow managed to rip both Clari and Trom's shirts off without causing them too much damage otherwise.
Saiyuki's protagonists do this quite a bit (particularly the 'older' three) and then there's Kougaiji who's a Walking Shirtless Scene for the first anime (he's got a jacket though which is just odd).
Kenren sort of counts in Gaiden too.
After he gets injured for the first time in Hyakujitsu No Bara Klaus makes a bit of a habit walking around with only bandages on his torso. Coincidentally, his shirt also seems to be the only clothing that comes off during sex.
Eiri Yuki of Gravitation gets this; the opening picture for this trope used to be of him (from a NSFW doujin).
Van of GUN×SWORD gets a few shirtless scenes. What's really interesting is that in flashbacks from before his fiancee's death, he seems to be a Walking Shirtless Scene. Maybe that's why Elena agreed to marry him?
Cherry Juice: These happen frequently with the male lead Minami, including on the very first page of the manga. This is a mixture of both Mr. Fanservice, and Author Appeal for the female Mangaka.
This happens a bit in Rurouni Kenshin, though canon-wise, it happens the most during the Kyoto arc. Most memorable would be when Sanosuke fights his ex-teacher Anji (Sanosuke throws his shirt off while Anji's explodes due to sheer rage and power), and later when Kenshin gets his blown off by one of Shishio's gunpowdered sword attacks.
In the first season of Star Blazers/Space Battleship Yamato Wildstar does hard physical exercise to angst. In a later episode, affably evil Desslok is in his bath and learns that a general has returned. He stands and the camera focuses on his chest... and stays there for about five seconds. This fails as fanservice immeasurably, however, as Desslok (going by this screenshot) has no nipples.
During episode 20 of Black Butler, Sebastian is arrested and chained up in some kind of torture room. And the first thing the creepy Torture Technician does is rip his shirt, giving us a nice shot of his abs. And many fangirl Squee's were heard.
Yoshimori from Kekkaishi gets a few shirtless scenes in the anime. His kekkai training was used as an excuse on both occasions in episodes 8 and 42. Episode 42 even included a scene in which he removed his kekkaishi robe with rapid fire precision.
Kotetsu T. Kaburagi (aka Wild Tiger) has a prolonged Shirtless Scene in the ninth episode of Tiger & Bunny. Being significantly older than most anime protagonists or superheroes has not made his Heroic Build any less heroic. He then gets another prolonged shirtless scene in episode thirteen, which ends with, well, this◊. It should come to no surprise that Tiger & Bunny fans love Wild Tiger.
In the same episode, the buff and athletic Tomitake is shown in nothing but a speedo as well, the muscular bear bellied chief, Oishi, is shown in revealing swim trunks, and the slim bishounen, Irie is shown in slightly shorter but less revealing slim trunks. They call themselves "The Four Soul Brothers of Heavenly kings".
Crim in .hack//SIGN gets a full shirtless scene later in the series.
Guts from Berserk has these all over the place.The best come in volumes 9 and 10.
Happens a surprising amount to InuYasha, usually after taking off his outer kimono and giving it to Kagome.
This happens most notably during his fight with Goshinki. After sustaining serious injuries the previous episode, he spends most of the episode running around in his undershirt at most. Then Goshinki breaks the Tetsusaiga, and while he's still in shock slashes him with enough force to tear his shirt to ribbons. He gets better, unlocking his demon blood and carrying out the rest of the fight with no shirt on and much focus on his abs.
In Saint Beast, Judas has a few, usually with water keeping it from being more than just shirtless.
Kougami in Psycho-Pass has a couple of shirtless workout scenes showcasing his lovingly-drawn chest and abs. Akane certainly seems appreciative.
In Pokémon Ash has gotten shirtless a countless number of times throughout the seasons and movies though the excess of it and his young age can cause it to be considered Fan Disservice. Even Brock and Cilan joins in at times.
Shobu Kirifuda from Duel Masters got a really long one (4 entire volumes) in the FE manga when he landed up in hot as hell Egypt.
The Legend Of Mother Sarahgender flips and deconstructs the trope at the same time. As she's working in the refugee camps, due to her unusually tall and powerful stature, Sarah is forced to work alongside the men, shirtless and bra-less, which of course attracted a lot of ogling from her co-prisoners. What happens next is neither sexy, nor positive for poor Sarah.
Chapter 53 of Attack on Titan has probably the first major shirtless scene of the entire manga so far courtesy of Eren. And he is apparently ripped. One can only imagine the fangirl reaction.