The graphic novel Asterios Polyp does an interesting treatment of this: Asterios is a Jerk with a Heart of Gold who hogs the spotlight and flashbacks to the days when he was married showed that his wife certainly felt that he smothered her at times by having to be the center of attention and make everything about his issues, but he's not quite this. He does have the heart of gold after all, and throughout the course of the story he learns to be better. Obnoxious and unlikable Jerk Ass theater director Willy, on the other hand, who is sometimes presented as being Not So Different and who shamelessly attempts to seduce Asterios' wife really is this, and will use, abuse, and then discard people and projects according to his whims.
Cerebus is a low-key version. He isn't portrayed as openly arrogant or egotistical, but he's described at one point as having "a self-absorption that borders on the pathological." Every decision he makes and every action he takes is done to satisfy his desires and whims and to fulfill what he thinks will be better for himself, with consequences to others coming second, if they occur to him at all. Even when he seems to be in normal interactions with others, this "me first" tendency is bubbling under the surface. This gets him into trouble in many, many ways over the course of the comic, upsetting plans and fracturing friendships and deeper relationships, and leads to his eventual downfall when his inability to learn from his mistakes ends up costing him everything.
Darkseid has a tremendous ego even for a God of Evil. His entire goal is to make everyone and everything an extension of himself. His vision of the future is to essentially turn all creation into an everlasting monument to himself.
Doctor Doom, the man even goes as far as to rename the capital of Latveria after himself. He also thinks everyone is inferior to him.
It's even been revealed that Doom's armor records every word he says, and these are transcribed to multiple different storage methods (paper, microfilm, flash drives, hard drive, etc.) so that they will be preserved for posterity.
The series 52 deals with the "missing year" of DC comics between the Infinite Crisis and the One Year Later storylines. In this timeframe Superman has lost his powers and is living life as Clark Kent while a new superhero, christened Supernova, has stepped in as the new protector of Metropolis. Lex Luthor, however, is convinced that Superman is Supernova, simply in a new disguise. Why would Superman do this? Why would he create a new identity, give himself new powers and sever all ties with friends and allies? Why go to all this trouble? To toy with Luthor.
Once he got his powers back, Superman proceeded call Luthor out about his claims of Superman "holding humans back". Pointing out that while he was gone, Luthor had spent the entire year obsessing over him rather than doing anything useful.
Luthor has always been like this. He smashed a chair over Doomsday's inert body because he wanted to be the one to kill Superman, assumed leadership of the new Injustice Gang when Superman became leader of the Justice League as he felt that was Superman 'throwing down the gauntlet', gave away his baby daughter to gain control over Brainiac 13's future technology, and hired someone to frame Bruce Wayne because he cancelled contracts in protest of Luthor's presidency.
Lex may just be the trope codifier for this one. He is so incredibly self-obsessed that he has formed this view that any and all actions taken to destroy Superman, whom he can only perceive as a threat to him, is justified so that he can be Earth's saviour, even though he couldn't care less about anyone who gets hurt in the process and it's clear it's all only for his own sense of pride; he also feels that everything Superman does is about undermining him, incapable of accepting that Superman would do all that just because he's a good man.
This tendency of Lex's has actually helped Superman a few times. In spite of meeting and interacting with Clark Kent several times, at points even being his childhood friend, the supposedly genius Luthor has never been able to pick up on his Paper-Thin Disguise. This is partly because Luthor refuses to believe Superman could possibly have a life totally independent of opposing him or do anything else with his time. He also projects his own arrogance onto Superman, believing him to be so full of himself that he would never pretend to be a normal human when he can spend all day lording over mankind as a God-like alien. He's so bad about this that he fired a private investigator who found proof that Superman is Clark Kent.
Even Luthor's more humanist tendencies introduced in later comics tend to be framed in this fashion. He frames his distrust of Superman as a fear that humanity is becoming meaningless and irrelevant by worshipping a super-powered alien who is far from human, but it's pretty clear that the main reason Luthor resents this is because he believes humanity should be busy worshipping him instead.
In the Elseworlds tale Superman: Red Son, Luthor is hired by President Eisenhower to find a way to destroy Superman, who is the Soviet Union's new superweapon. After a few false starts, Lex finally finds his motivation — not from his ideological differences with the Soviets, Patriotic Fervor, or even the Fantastic Racism he's often depicted with — but from being beaten at chess by the flawed Bizarro clone he makes of Superman. The idea that someone on Earth might be smarter than him is so personally offensive to Luthor that he destroys all his notes on the Bizarro clone's creation (and murders his colleagues on the project) and dedicates the rest of his life to Superman's annihilation.
The beginning of the story arc Superman: Grounded features Superman being slapped by a woman upset for her husband's death after the events of New Krypton. Thing is, her husband died of a brain aneurysm, not in the Earth-New Krypton war. She claims Superman could have saved him but Superman was away on New Krypton, attempting to prevent war from breaking out in the first place. If anything, she comes across as selfish and entitled in the middle of an international tragedy.
In the CrossGen graphic novel series The First, the gods of House Sinister live by this trope. In fact, part of Ingra's speech is to "place the self before all".
The original Reverse-Flash, Eobard Thawne. He cares for nothing but himself and irrationally blames Barry Allen for everything wrong in his life (although it is suggested that this may be the result of a repressed memory, as his 'first' trip to the past saw him learn about his future death at Barry's hands only for him to consciously forget it after taking a beating from Barry's successor Wally).
Invoked in Gotham Central, where Renee Montoya's brother believes that she is actively trying to hurt their parents by being more concerned about herself instead of them regarding what her homosexuality would do to them if they found out.
In The Just #1, Earth-16 is a world where the children of superheroes and supervillains are celebrity darlings since there's no more crime to fight (to the point where the contemporary Justice League roster has done nothing but battle reenactments). The solicits and cover refer to this world as "Earth-Me."
Green Lantern: This page, everyone mentioned on it and everyone who's contributed to it, belong to Larfleeze, The DCU's embodiment of Greed.
In Legion of Super-Heroes, the serial killer Roxxas arrived on planet to kill Legionnaires and spotted another villain, Mekt Ranzz, Lightning Lord. He offered to share the kills. Unbeknownst to him, Mekt had reformed and was there because his brother and sisters were Legionnaires; first he appealed to Roxxas to stop, and then joined the fight against him. When Roxxas downed all his foes, he kicked Mekt and complained that he would have shared.
In another strip, she read a book of Christian prayers and noticed how frequently the expression "mea culpa" was used. She then proceeded to stay up reading it all night trying to find a prayer that allowed her to pass guilt on to other people to no avail.
In yet another strip, she is shown reading about grisly murders and crimes on the newspaper and referring to it as "reading about what a good person [she] is" (by comparison).
When Mafalda reads some statistics about what will happen in the event of nuclear war, particularly how many people will die indiscriminately, Susanita laments how disgusting it would be to die with random strangers, essentially comparing it to sex.
Inverted in My Little Pony Micro Series Issue #2 . In the end, Rainbow realizes that turning her own attitude around isn't enough; she needs to instill happiness and inspiration in everypony else.
Played subtly in Ultimate Spider-Man. Norman Osborn is convinced he's the most important thing in the lives of everyone he knows. He believes he's the single greatest threat Nick Fury has ever come across when he's really just a particularly annoying blip on Fury's radar. He also thinks that Peter Parker looks up to him like a father and needs his guidance, then when Peter attacks him is sure that Fury twisted him against him. Twisting it even further, he believes he owns Peter, having made the spider that bit him (even if the incident that created Spider-Man was a total accident). This means that he has the right to force him to do whatever he wants and kill him if he refuses.
616 Osborn as well. As this quote illustrates:
"My father used to say to me, "it's not all about you." I told him I was working on it."
- Norman Osborn, Dark X-Men #4
Cassandra Nova from Grant Morrison's run on X-Men. A psychic parasite who accidentally became Professor Xavier's stillborn-but-not-really twin sister, Cassandra believes that the universe is still the womb she shared with Xavier, in which she has to completely destroy him in order to be "born." Therefore every living being she encounters is either not real or a mindless drone Xavier conjured up. This lets her commit psychological torture, wreck an interplanetary civilization, and initiate a genocide with pure sociopathic impunity.
In Astro City, Infidel thinks more of the names hurled at him than of the objections that he kidnaps people for experiments.