If you're looking for a job, here's a list of successful, influential corporations you might want to work for. That is, as long as you don't ask too many questions.
LexCorp (DC Comics)
Hailed as one of the largest, most diversified multinational corporations in the world, it also happens to be founded by Lex Luthor, who runs it with his characteristic ruthlessness. The list of cities and countries where the corporation has holdings is basically as long as the list of cities and countries on Earth, and the number of companies controlled by LexCorp is almost as long and just as varied. Unfortunately, as of One Year Later, with Lana Lang acting as CEO, the corporation seems to be heading towards bankruptcy. The "No Helping Superman" rule still applies to all employees, however.
The Primatech Paper Company of Odessa, Texas is the first Primatech facility the show introduces us to. Of course, they do a lot more than just make paper—They capture and "study" folks with enhanced abilities, but, really, what they do best is operate in a moral gray area. A very dark gray area.
Blue Sun (Firefly and Serenity)
While it's still unclear exactly what the corporation does, it seems pretty implicit that it isn't good. Although most of the Blue Sun products seen on the show seem as innocuous as coffee cans and crackers, River's actions, such as ripping off their labels on food and slashing Jayne with a knife when he wears their logo, suggest that there's something more going on. Some suggest that there's something in the food, but the stronger hypothesis seems to be that Blue Sun is somehow connected to the experiments done on River and is perhaps working with the Alliance.
Merrick Biotech (The Island)
Merrick Biotech's business is keeping clones of their customers around, just in case said customers should need a transplant of some kind. Basically like the ultimate life insurance, right? Except for the fact that it's illegal to allow the clones to be conscious and sentient, which, of course, Merrick Biotech lets happen and lies to their clients about. Therefore, the corporation has an entire population of fully-conscious human beings living totally unaware of the fact that they're basically just an organ farm. And that's just not cool.
Fatboy Industries (The Middleman, TV series)
In the final episode of the series, Wendy Watson is transported into a classic example of a Mirrorverse, where the megacorp of Fatboy Industries is a totalitarian presence, having taken the place of the government. Unfortunately, the morality of Fatboy in Wendy's real world is still unconfirmed, as there's a hint of "more than meets the eye" to both the corporation and its ambiguous founder, Manservant Neville. (This is underscored by the fact that the rest of Mirrorverse turns out to be not so very different from the real world.)
Buy n Large Corporation (WALL•E)
While maybe not inherently evil, the Buy n Large Corporation did govern Earth (perhaps much like the Mirrorverse Fatboy Industries) and did a very poor job of it. Even if rendering the planet uninhabitable wasn't exactly the gameplan, Buy n Large's role in that happening probably makes it a worse corporation than most of the others on this list.
Tyrell Corporation (Blade Runner)
The Tyrell Corporation produces the replicants, lifelike androids designed to the work deemed to dangerous and demeaning for humans, and is named for Dr. Eldon Tyrell, the founder and genius inventor of the replicants. While it's debatable how truly "evil" the Tyrell Corporation is, there is a definite sinister quality to their dealings and it's nigh impossible to deny that they definitely smack of "evil corporation."
Veidt Industries (Watchmen)
A lot of what was said about LexCorp could be repeated here. Once again, the ruthless ambition of the corporation paired with the questionable morality of its founder leaves us wondering how much to trust this (powerful, financially successful) corporation. Meanwhile, the impending release of the film was paired with a Veidt Industries commercial contest, leading to all sorts of fake '80's advertising:
Weyland-Yutani (Alien franchise)
Perhaps the gold standard of evil megacorporations, Weyland-Yutani's main gig is merciless profiteering, no matter what (or who) needs to be sacrificed in the process. (Fun fact: Their logo can be seen on some of the weapons in Firefly and they're said to be a client of Wolfram and Hart in Angel. Maybe this has something to do with the fact that Joss Whedon wrote Alien Resurrection.)
Cyberdyne Systems Corporation (Terminator films)
While the corporation is said to be benign in the first two films, manufacturing parts for bigger companies, they then make the mistake of creating Skynet, a system of artificially intelligent supercomputers that control (among other things) nuclear missiles. This was not a smart move. In fact, it's just un-smart enough to warrant Cyberdyne's inclusion on this list.
Yoyodyne (The Crying of Lot 49 and V. by Thomas Pynchon)
Yoyodyne is a defense contractor that's described in The Crying of Lot 49 as "a giant of the aerospace industry," and a few characters in the novel work for the company. While the morality of Yoyodyne isn't firmly sealed either way, the thread of conspiracy woven throughout the work suggests that it isn't all it seems. (The name "Yoyodyne" is mentioned, as you might remember, in The Adventures of Buckaroo Banzai Across the 8th Dimension.)
Earth Protectors (Up, Up, and Away, 2000 TV movie)
Ostensibly a group designed to teach middle schoolers the importance of environmentalism, Earth Protectors' favorite method of persuasion is brainwashing. And while handing out CD's brainwashing kids into recycling isn't a completely bad thing, brainwashing the parents to rob banks is another thing entirely. (Actually, brainwashing in general? Not recommended.)
Omni Consumer Products (Robocop)
Described as dystopian and inhumane, Omni Consumer Products (OCP) is an example of military capitalism taken to the extreme, until the corporation no longer cares who gets hurt or killed as long as the PR stays good. OCP is depicted as having its fingers in almost every branch of life, as long as there's money to be made from it. One of their strokes of genius comes from running both criminal organizations and a private police force, thereby ensuring a continued demand for both crime and justice.
Soylent Corporation (Soylent Green)
It's 2022 and the world is overpopulated and hungry. Who better to step in than the Soylent Corporation with their rations of tasty wafers known as Soylent Red and Soylent Yellow? Well, okay, they aren't that tasty, but thankfully, Soylent's come out with a new flavor: Soylent Green. Much more delicious. So what's the catch? Well, we all know what Soylent Green is.
GeneCo (Repo! The Genetic Opera)
After an epidemic of organ failures, GeneCo steps in to give transplants to those in need. Benevolent, right? Well, sure, until the boss, Rotti Largo, gets permission to repossess the organs of people who renege on their payments. And once a corporation is taking out your insides, the benevolence is kind of gone.