Avatar: The Last Airbender: Ozai is a complete sociopath. While Azula has tendencies, she is revealed to have a deeply buried conscience, and is nearly completely dependent on her father's approval, making her more of a narcissist. Ozai, by contrast, doesn't seem to feel anything for anybody but himself. Not his son Zuko, his daughter Azula, his brother Iroh... he doesn't even bat an eyelid when admitting he framed and banished his own wife! The saddest part is that neither of them used to be this way, but the conditions in which they group up and the parental influence on them shaped them into being such uncaring, self-centered monsters. Word of God has it that, since she's still just a teenager, Azula might get better with time. Ozai... not so much.
Unalaq has a superficial charm which he uses to put a rift between Korra and her father, as well as Korra and Tenzin so he can become Korra's spirituality teacher. He fakes caring about his brother Tonraq (Korra's father), Korra herself, and Eska and Desna while things are going his way and honestly seems surprised when people object to his fleet taking over the Southern Water Tribe. And when all of his pretense is stripped away, he becomes a cruel, absolutely heartless man who cares for absolutely no one. Not even his wife in the North, nor his son and daughter. All he cares about is his power and increasing it, to the point of releasing the equivalent of Satan himself, Vaatu and then merging with it to become the equivalent of the Anti Christ. To this end, if he has to kill a 11 year old girl or even his own niece, he doesn't care.
Earth Queen Hou-Ting. Reviewing her key personality traits is like reading through a sociopath diagnostic checklist: superficial charm, a grandiose sense of self, pathological lying, a penchant for manipulating others to achieve her own ends, an absolutely astonishing lack of empathy or remorse for any of her actions, and an insatiable lust for dominance and importance that drives her every move. She has no qualms whatsoever about sacrificing those closest to her if it suits her purposes.
Eric Cartman is a perfect example of a sociopath with particularly poor impulse control. First of all, he displays zero empathy for any living person, nor has he ever shown any feelings of guilt for anything. His list of crimes is vast, but he has committed them frequently just to alleviate boredom, or for an immature personal gain. When he thought he was dead and a ghost, he endeavored to atone for his sins, but only did so to stop being a ghost - he didn't consider he might otherwise go to Hell. He showed no sympathy for the suffering Butters went through for helping him, and once he realized he hadn't been a ghost, he considered all these acts of atonement a waste of time.
Saddam Hussein is a worse sociopath than Cartman, even though it provides Comedic Sociopathy. Megalomaniac, only cares about himself, extreme lack of empathy, makes atrocities For the Evulz, and shows extremely perverted and sadistic tendencies.
Sheila Broflovski has sociopathic traits in The Movie, too.
Lennart Bedrager, one of the Big Bads of season 20, could qualify as a sociopath. He attempts to intentionally cause World War III for no other reason than his own amusement.
Kevin 11 from Ben 10, and when the Time Skip sequel shows had him become good, first Kevin's Evil Counterpart Darkstar and then the evil alien Aggregor came around to fill the void.
Ultimately, it's revealed that for Osmosians like Kevin and Aggregor, using their powers to absorb energy (which Kevin did as a kid, and Aggregor still does) induces a sociopathy-like state. Kevin stopped absorbing energy before Alien Force began, which was what allowed him to regain his sanity.
Omniverse gives us Malware. A mutated Galvanic Mechamorph appropriately described by Ben as a total psychopath. Before his upgrade, Malware started out feeding on other Mechamorphs to sustain himself. Arrogant and devoid of any moral compass, he even had the gall to claim that they deserve to be destroyed. When he finally got his upgrade, he became even worse. One episode had him attempting to murder a busload of innocent children to make a quick escape from Ben. Then the Showdown 2-parter revealed that in the past he Destroyed Feedback, one of Ben's alien forms, soley to hurt the boy out of spite. Then he proceeds to top that by destroying his own homeworld.
Lamilton Taeshawn. He's a monstrously wicked hoodlum who commits many crimes, including beating up his extreme doormat of a grandmother, shooting a chained guard dog to death, and trying to kill his "friend" Riley. He admits to feeling no real empathy or remorse, and states his motives as just "it's fun doing bad things".
Ricardio is an almost perfect example of a sociopath in the show, combined with being Ax-Crazy. He's incredibly smart, he can not empathize with others, almost tried to cut off Bubblegum's heart and almost killed the Ice King with a sadistic joy, and tried to mutilate Lady when she was pregnant. All this with no remorse.
Goliad has no empathy for others. She honestly believes that she has the right to do whatever she wants just because no one is powerful enough to stop her.
Freudian Excuse aside, Magic Man really is a true sociopath. He is impulsive, psychotic, sadistic, and his ways to play tricks in every living thing closely resembles The Joker.
Most of the bad guys in X-Men: Evolution have shades of this. The Brotherhood is primarily filled with narcissistic and amoral mutants who, despite often been said to be more 'sympathetic' than normal, they're anything but when you take a good look at it. Pietro was self caring and allowed a train of bystanders be derailed and let it crash into one filled with fuel. Blob kidnapped Jean and showed incredibly creepy, rapist vibes, as well as other violent behavior. Toad was amoral, selfish, vulgar, and cruel, with his attraction to Wanda being his only redeeming quality. Avalanche was aggressive and violent, and while he looked rather sympathetic in the second season, a number of things made it look like he was faking the nice guy persona he had during that season. Of the Acolytes, Pyro and Sabretooth are the closest we get to text book Sociopaths in a show for kids; the two attempted murder, enjoyed their work, and are the definition of why mutants may be a risk. Averted with Colossus and Gambit; the former a good guy forced to work for bad people, the latter a Card CarryingVillain.
Peter Griffin qualifies in his worst moments, with his cruel, sadistic, and insensitive treatment of his daughter Meg, and throwing an unconscious Stewie underneath Lois' car to blame her for his condition.
Vlad Plasmius also counts. He has all the traits listed on the main page, and his "love" for Maddy is shown to be shallow and mostly for her beauty; he tries his best to repress her strong personality and forcibly forge her into a "model wife" in the bad timeline where he gets her.
Despite heavy censorship, Spider-Man: The Animated Series still managed to make their version of Cletus Kasady, aka Carnage, into a bonafide psychopath, portraying him as a Laughing MadBomber, who cackles with glee at the possibility of vaporising a city block—himself included—in his first appearance. He shows no remorse for his actions, and after becoming Carnage is downright eager to get back in action and start stealing souls for Dormammu (an Omnicidal Maniac who will consume the souls of everyone in the world if he is unleashed). He displays no regard for human life (least of all his own) and goes out of his way to injure anyone who tries to help him, including his psychiatrist, Anne Kafka.
Young Justice Klarion the Witch boy plays this role as a member of The Light.
In Gravity Falls there's Lil'Gideon: he acts like an adorable kid one minute, and swings to a total jerk the next, he is willing to use any diabolical scheme to get revenge on the Pines family and killing people is no problem to him.
Lightning Dust's status as Shadow Archetype to Rainbow Dash is principally due to her ruthlessness in her attempts to become the greatest flier in Equestria, which results in a total lack of concern for the ponies around her even when it comes to the point that she endangers their lives. She also works in a good deal of emotional manipulation in her interactions with Rainbow Dash.
Lord Tirek from "Twilight's Kingdom" feels no empathy for anyone he hurts as long as he gets his way and will manipulate anyone he pleases to serve his ends. If even Discord finds you repulsive, you definitely qualify.
Starlight Glimmer from "The Cutie Map" is a nasty combination of paranoia, and this. She's focused on removing the cutie marks of other ponies (their very life's essence) purely to advance her version of a perfect society, demanding everyone else live by her rules while not following them herself, manipulative, and maintains an outward image of benevolence but won't hesitate to physically hurt or mentally torture dissenters. Most telling, when revealed as a hypocrite, she accuses others of ruining her life and ends her appearance by twice refusing to admit any wrongdoing, still convinced it was her victims who rebuffed her generosity. It takes literally seeing how her actions in taking revenge cause The End of the World as We Know It in one Bad Future that she finally surrenders and makes a Heel–Face Turn, and it's shown in multiple episodes afterwards she has problems connecting with others on a personal level, preferring to use magic as a "quick and easy" method to solve her friendship problems and has problems properly reading social cues.
As seen in "Rarity Investigates," Wind Rider, a retired Wonderbolt (and Frame-Up artist, according to Word of God), goes to great lengths to preserve his flight record. He seems positively unconcerned that Rainbow Dash considered him her primary idol and thus the main reason she wanted to be in the Bolts. At least Lightning Dust has her whole life ahead of her.
Mr. Burns, anyone? He is a frequent Lack of Empathy, exploits several employees, makes some misdeeds For the Evulz, and tried to kill Bart. His sociopathy is considerable specially in the early seasons, not for nothing he's the most hated man in Springfield...
Then we have Bob's brother, Cecil Terwilliger. He's a impeccable mastermind sociopath, who tried to kill two children and his own brother in his first plan.
Eddy's Brother from Ed, Edd n Eddy's Big Picture Show. Let's see: lack of empathy, even to their family (to Eddy) and is incapable of remorse. And where does all this transpire? Where does this guy live? A trailer at an amusement park. Yes, the implication is obvious: he gets to torment kids every single day. His whole life is just getting off on bullying those smaller and younger than him.
In Star Wars: The Clone Wars, Darth Maul definitely qualifies. Lack of Empathy? He's either killed, tried to kill, or would be willing to kill almost everyone he's come across in the series, and even his one Morality Chain in his brother Savage Oppress at multiple points looked like he was just as expendable. Consummate deception skills? He managed to con Pre Vizsla into an alliance, and it was Maul's plan that convinced Mandalore that the Death Watch were heroes and liberators. Superficial charm and persuasion? He manipulated Vizsla, Almec, and legions of criminals into serving him. Troubling childhood? He was "raised" by Darth Sidious. Maul is a high-functioning example, but he fits all the criteria of a sociopath.
Palpatine, aka the Sith Lord Darth Sidious, is the mastermind of the Clone Wars and is willing to sacrifice anyone and anything necessary to achieve total domination over the Galaxy.
Stan Smith fits the criteria too in early seasons. He can't recognize other people's feelings, had a complete Lack of Empathy, and views himself as more important than he really is.
Drawn Together is a series FULL of sociopaths. Even to get a real kick out of that everyone are this, excluding Foxxy, Xandir, and Wooldoor.
Spanky Ham is the perfect example. Lack of Empathy, deceives or puts people in horrible situations for their own convenience, is unpleasant, obnoxious, sadistic, greedy and manipulative.
Captain Hero is not far behind either. He is a frequent lack of empathy, not afraid to do heinous acts, has a problem of childhood, even raped his own parents.
Princess Clara is close as well. She's racist, homophobic, and rarely feels pity for anyone other than herself. Often, she will indulge in racist theories about other races' intelligence. She also thinks that she should be the one to be raptured instead of everyone else. Upon realizing that she was not "raptured", she sees no shame in getting in trouble.
Zapp Brannigan shows all the classic signs of sociopathy - he's manipulative, without guilt for any past actions, arrogant, egotistical, and an exceptional liar - he manages to convince our heroes on a regular basis into believing he may have changed. And of course the fact that he places a value of exactly zero on any life other than his own. Perhaps this is best seen in a combination of how he treats his own troops as pure cannon fodder, and the way he manages to keep his own job despite his regular displays of incompetence.
Derek Powers, aka Blight, from Batman Beyond is a pretty major case. He essentially regards others as tools to fulfill his motives, only cares about power, regularly manipulates and uses people under a veneer of charm, and when he learns that he killed Batman's father, he casually replies "Do you have the slightest idea how little that narrows it down?"
From Scooby-Doo! Mystery Incorporated: Professor Pericles, Mr. E/Ricky Owens and both Brad and Judy Chilles when afflicted by the curse. As long as they get to the treasure connected to the curse, they'll do anything for it.
Scarlett is also one who would have killed the entire cast without a seconds hesitations if she hadn't been stopped.
The Title Character of Kevin Spencer. He regularly breaks the law just because, looks out only for himself most of the time, and is able to manipulate people into thinking he's on their side when he wants something from them. A good example would be how he pretended to be nice to his dad in order to lure him into a false sense of scrutiny, before ratting him out to the cops and collecting a reward.
Wander over Yonder: Lord Dominator. Despite being a dorky teenager, its clear she is completely heartless, and utterly ruthless about conquest. If her minions fail in their duties, she has no problem throwing them into space and letting them burn up in the atmosphere like someone disposing of an old appliance. And then there are her motivations, revealed near the end of the second season: she doesn't want to rule the galaxy, but rather destroy it, for her own personal entertainment, as she finds suffering and destruction fun. As soon as she's finished with one galaxy and can no longer derive the stimulation she craves, she moves on to the next. She doesn't understand concepts like friendship, sacrifice, and morality, totally rejecting Wander's offer of redemption in the series finale, and is left to live out the rest of her days depowered and alone.
Marvin the Martian from Looney Tunes is utterly devoid of any remorse or concern for others, and gives destroying a planet and murdering billions of people the same regard as taking out the garbage.