This has always been Alan Moore's principal sense of humor. You're always going to find at least one moment like this in anything he writes. His work from 2000 AD is especially notable as black comedy is usually the entire driving force behind all his stories published there.
Zombo: Much of the comic's humor is derived from people getting killed in incredibly gory and violent ways.
Anything by Jhonen Vasquez, from Johnny the Homicidal Maniac to Invader Zim. The main point of the former, particularly the early comics, is to show horribly brutal deaths and tortures. As things progress and Johnny gets more and more talky the violence begins to tone down, but that over the top violence remains at the core of most of the comedy in the strip.
Squee!!, by the same author, follows a Johnny's child neighbor through a series of considerably disturbing adventures, such as his grandpa trying to eat him and a strange trip to a public bathroom.
Fillerbunny is all about seeing something cute in inordinate amounts of pain.
And then there's the Bad Art Collection... And Jelly Fist...
Oddly, I Feel Sick, despite being another spin off of Johnny, tones this down considerably, favoring a stranger brand of humor. "Cat had acid for blood..."
Most of Garth Ennis' works, especially The Punisher, The Boys, Preacher, and Hitman. Preacher's best-known example would have to be Arseface, a character who manages to render himself hideous in a failed suicide attempt and pursues Jesse Custer to avenge the death of his father — caused by Custer using his Voice of God power to order him to "Go fuck himself." Which he did. And then committed suicide.
[Deadshot kills General Kerimov] Hawkgirl: You killed him. Deadshot: What, it was self-defense. Guy obviously had a gun. Hawkgirl: He didn't have a gun, Deadshot! Deadshot: Okay, so it was murder. Who cares?
The Joker's whole shtick is making dark jokes about the murders and other violent crimes that he commits. He gets carried away with it to say the least.
Lenore the Cute Little Dead Girl is about an undead ten-year-old girl who frequently and obliviously kills the animals she keeps as pets, among other hilariously gruesome things.
In a comic that parodies the Chick Tract "Lisa", a man who sexually abuses his daughter is suddenly overcome with guilt over what he has done to his child, and decides that only God can forgive him for his crimes. After having confessed to a priest, who bestows forgiveness on him, the man heads home, feeling like a new, happier person, ready to start completely over... with abusing his daughter again.
The comic gets a lot of mileage out of this trope, showing just just how violent and psychotic a person would have to be to actually pull it off as a superhero.
The scene where Big Daddy shoots Hit Girl and explains that it won't hurt.
Notable example in Volume Two, Issue 4: Red Mist/The Motherfucker's crack about iCarly losing a few viewers during his suburban massacre.
The Motherfucker's line before Gangraping Katie:
The Motherfucker:You're done banging superheroes baby, it's time to see what evil dick tastes like.
Clarissa, also known as Family Portrait, is a comic about a young girl who is the victim of Parental Incest and whose family are a classic case of 1950s Stepford Smilers. It's not as amusing as other examples but can still be sickeningly funny.
Belgian comic strip Violine definitely qualifies. Ten-year-old Violine has the ability to read people's minds by looking into their eyes. Her adventures include rescuing mice from being dissected (she even sees one cut open, and vomits), being perceived as a witch and chased by people who want her dead, hopping into a car with a pedophile (and seeing an image of herself bound and gagged and looking terrified when reading his mind), being thrown off a ship that she got caught stowing away on by a crew that assumes she's dead, witnessing the dead bodies of many birds caught in an oil spill, being chased by men with guns who then get eaten by alligators, and many more. All of this is played for very dark humor. Or you could possibly interpret it as a serious story that just has dark jokes scattered throughout, but either way, the sources of humor are pretty morbid.
Evan Dorkin's Fun with Milk & Cheese series was about two hyperviolent dairy products who spend every strip of theirs beat the ever loving daylights out of everything they hate. And they hate everything except for liquor, TV, and each other. It's actually hard to describe the level of brutality involved. To put it in context, at one point, a guy from the Guinness Book of World Records shows them as they're beating a hippie pot dealer to a bloody mess and crowns them as "World Class Abuse Kings".
Icelandic playwright/cartoonist Hugleikur Dagsson's crudely-drawn cartoons include such savory topics as incest, coprophagia, bestiality, suicide, and adults intentionally putting children in harm's way. Check it out if you dare.
Hubba Hubba, a two-page comic by Arthur Suydam that appeared in Heavy Metal. One of Suydam's trademark weirdos-with-snouts sees a beautiful naked woman and, hoping to impress her with a gift, kills and cooks what he thinks is a small animal. This turns out to have been the woman's baby, and you're meant to see her horror and his ignorance as to its cause as humorous.
Sin City can get this way with its over-the-top violence. Jack Rafferty's death, for instance, goes on for many pages as he's slowly chopped up by Miho, making empty threats in the process while the the typically violent Sin City heroes gradually become more squeamish. At one point, Jack seems aware of how stupid he must look and shouts "Nobody laugh! This isn't funny!," as he crawls around with Miho's manji shuriken sticking out of his butt.
The Swedish comic Hälge, being primarily about the lives and interactions of moose and hunters, constantly uses this trope. And when it isn't, it's using Irony or just plain jerkassery instead.
Fortress Maximus: Okay, my demands haven't been met, one of you is about to die. Whirl: Ooh Ohh! Pick me! Rung: Okay, calm down, we can talk about this. Whirl: Don't listen to him, he's trying to distract you, pull the trigger!
Brainstorm is also responsible for a fair bit, given that his hobby is creating impractically sadistic, excessive or otherwise insane weapons solely to annoy the Autobot ethics committee. He's also The Smart Guy - one of them, at least - on the ship, meaning that we get exchanges like this one, where he discovers that a member of the crew has suffered a horrible fate during a quantum drive malfunction:
Brainstorm: The first rule of interstellar travelnever stand next to a quantum generator when it's about to flout the laws of physics. Rodimus: So who broke the rule? Brainstorm: Um... good question. One of the Duobots, I think. Shock? Ore? I can never remember which is which...The blue one. Ore. He's sort of been what's the scientific term? totally mashed into the generator itself. Rodimus: That sounds that sounds terrible. Brainstorm: Oh, in many respects it is. But look on the bright side: at least it'll be easy to tell 'em apart from now on.
Much of the humor of Pocket God comes from the deadly mishaps that befall the pygmy tribe. Fortunately for them, they can resurrect themselves. Dying for them happens so often, they made games centered around who stays alive the longest.
In the first issue of Sex Criminals, main character Suzie begins her narration with her and her boyfriend about to be arrested, then goes on to relate the story of her father getting murdered, all the while insisting she's going to start joking soon.
The cartoons of John Callahan often dealt with gags full with black comedy, often about handicapped people. This created outrage among many readers, despite the fact that he was a wheelchair user himself.
Les Femmes en blanc: A Belgian comic strip about nurses and doctors in a hospital. Many gags revolve around operations that go wrong, sometimes with patients dying as a result. Did we mention its actually a gag comic and even manages to be funny?
Pierre Tombal: Another Belgian comic strip about a gravedigger in a cemetery who treats his corpses — all living skeletons! — as residents. Many jokes are about death and dying, but always done in an amusing, yet macabre way.
Urbanus: Extremely dark comedy! In Leute voor de Meute Urbanus is executed in a big budget spectacle where his torture is done in such a way that the audience will be entertained by it! In De Depressie van Urbanus he tries to get himself killed so that he can stay with his deceased girlfriend in Heaven. First he wants to commit suicide, but when he learns that the Christian faith doesn't allow such people in Heaven he tries to make his deaths appear as an accident.
The comics of Andy Riley, most notably the Suicide Bunnies gags, where every gag shows a rabbit trying to commit suicide in a creative way.
Dutch cartoonist Gregorius Nekschot was infamous for making a lot of offensive jokes about religion and the Second World War. At one point he was even arrested in name of the Dutch government for making discriminatory remarks, which was a huge deal, because many felt this to be a violation of the freedom of speech.
Robert Crumb and many other Underground Comics artists dealt predominantly with taboo subjects, including sometimes very offensive racial and sexist jokes.
The Belgian comic strip Cowboy Henk (translated as Cowboy Maurice in English) is notable for being very dark and offensive in its subject matter.
Quick and Flupke: Occasionally gags will end with the two school boys accidentally dying and ending up in Heaven.
The premise of Fred Hembeck Destroys the Marvel Universe revolves around all of the superheroes and supervillains of the Marvel Universe dying in comedic ways (e.g. Ant-Man getting put into a microwave oven by a kindly old woman, the X-Men being killed in their sleep by Ninja Sentinels, the Fantastic Four and Nathaniel Richards getting crushed by a boulder that appeared out of nowhere, etc.). There's even a clown-like version of The Grim Reaper named Crackers.
The Flintstones comic can dip into this sometimes, like the jokes about the monkey that is killed being shot into space.
Judge Dredd is well known for this. For example, during the Apocalypse War, the Sovs use a dimension warp shield to send 25TADs that Mega City One had launched at them to an alternate reality where Earth has been a hippie paradise for centuries. The hippies note how pretty the nukes look right before their world is literally shattered.
Italian comics tend to have this kind of humor:
Sturmtruppen is a satire whose protagonists are a German battalion during World War II, and almost all its humor is based on this. The author managed to actually make funny jokes on The Holocaust, if only to prove how evil, pointless and stupid it was.
Necessary in Dylan Dog due its nature as a horror comic. For example, the 2016 story "Baba Yaga" has a terminally ill man who had sold his soul to both the devil (who had not killed the murderers of his family as requested because he wanted to wait until it was too late for him to enjoy it) and Baba Yaga (who blew them up immediately after bringing him in the best place to enjoy the show) trying to kill himself, thus giving his soul to Baba Yaga as an aftereffect, only for the devil thwarting him every time in some ridiculous way (such as the attempt to stab himself in the heart: the knife's blade fell off on contact with his skin), much to the poor man's increased annoyance (to the point that when Dylan's assistant almost succeeds at killing him he's happy).