Subverted in Grant Morrison's comic series-cum-"memetic hypersigil" The Invisibles. In the very first issue, King Mob guns down a large array of cannon-fodder, all wearing helmets with visors. Later in the series, we see the life and times of one of these nameless mooks, and his widow eventually saves Mob's life, calling in medical help for him when she finds him dying of gunshot wounds. When asked about her motive, she replies that her husband was likewise gunned down.
In all incarnations of Teenage Mutant Ninja Turtles, the Shredder (or, in the comics, whoever's running the Foot Clan today) has an endless supply of completely masked ninjas for our heroes to kick the crap out of. When the shows wanted to have things busted up, they used Mecha-Mooks. The comics weren't so choosy about showing the actual death of living Mooks.
Subverted with the X-Men character Strong Guy. Guido started out as just an anonymous mook working for some bad guys... but then he reformed and joined the good guys. At the time, he joked that he was just doing it for the paycheck, but he has proven to be a worthy hero.
Used extensively in Marvel Comics in the form of HYDRA—and then deconstructed by Deadpool's new bud Bob, Agent of HYDRA. He explains that he's in for the great benefits, and also to impress his girlfriend (which doesn't work.)
And AIM, The Hand and HAMMER.
In a very early issue of Daredevil, the Masked Marauder explains why he started recruiting tried-and-true criminals rather than relying on his costumed peons as he did before. The reason? Simple; they were incompetant morons. In a meta sense, you can argue that his chances of success are increased dramatically because now his thugs don't even wear masks.
Not that Daredevil would notice what they were wearing.
Ouch, low blow.
In Empowered, being a superhero comic, there are mooks. Subverted by Thugboy's gang "Witless Minions", who stole from the villains they worked for. And definitely weren't willing to die for their bosses.
Sin City stories often involve the hero destroying an increasingy larger number of mooks before fighting the Big Bad.
In the Astérix comics, most Roman legionaries exist to get beaten senseless by the Gauls.
In All Fall Down, the Order of Despots have a small army of mooks on their moon base.
In the short-lived Harley Quinn spinoff, a mook who had once worked for the Joker commented that you worked for the Joker if something had really gone wrong in your life. Later, he even admitted that he'd long been aware of the likelyhood of being killed by Batman or the Joker himself.
Lampshaded in The Killing Joke, in which Batman notes that one thing has always remained constant in the Joker's long career: "The poor quality of his hired muscle."