In El Conquistador, the human sacrifices generally end with a humanitarian sushi...
Milliway's, The Hitchhiker's Guide to the Galaxy, serves talking cows bred to be absolutely delighted about their fate. Most characters accept a self-serving food source as ethically sound, but the less-travelled human protagonist can't partake. Without regards to the ethics of breeding or eating food that wants to be eaten, that the food can communicate and is thus intelligent could easily be considered cannibalism, especially in a story full of people who aren't human.
Commissar Gaunt of the Gaunt's Ghosts series discovered this happening on a large scale in His Last Command, much to his disgust, during an inspection of Post 16, where sickness and desertion rates among Imperial soldiers had been abnormally high. It turned out that the regimental cooks stationed there came from Fortis Binar, a Hive World that had recently been liberated from the Chaos Archenemy. Due to food shortages being endemic in the Hives during the War, it had become common practice to process the flesh of the dead for food. And while the new draftees for the regiment were unaware, the original staff were all old servicemen, who had either become habituated to the concept, or were corrupt and were selling the fresh food stocks supplied to them by the Munitorum on the Black Market to starving Guardsmen at highly inflated rates.
Played straight by The Culture in Iain M. Banks's State of the Art. Removing a few muscle cells doesn't hurt anyone, therefore why should eating the resulting vat-grown meat be bad? So, while a Contact ship visits Earth, one of the crew arranges a feast including the power figures of 1977:
"To Serve Man" by Damon Knight is a short story about a race of pig-like aliens called the Kanamit who offer Earth the benefits of their science in exchange for groups of earthlings to visit their planet. The title refers to that of a book which one of the characters managed to obtain. The book is revealed to be . . . a cookbook.
In the John Carter of Mars books, the White Martians subsist solely on the flesh of Red and Green Martians, considering themselves to be above dining on mere animals. The Black Martians, in turn, eat only White Martians.
In Thuvia, Maid of Mars, Komal eats men.
Yes, but... Komal is the Martian version of a lion, and doesn't have much choice in the matter; he's trapped and has to eat what the Lotharians (who believe him to be a god) send him to eat.
In one Science Fiction story by Arthur C. Clarke, "The Food of the Gods", people stopped killing animals for meat and instead grew tissue in vats. Then one company hit upon the idea of cloning and growing meat perfectly compatible with human needs, and...
The Roald Dahl short story "Pig" in the collection Kiss Kiss involves this. The main character has been raised to be a vegetarian by a relative who can't stand animals being killed for human consumption. After she dies and he ends up trying pork, he asks to see the slaughterhouse where it's prepared...and it turns out that it doesn't just slaughter pigs.
Also used in The Witches, in which it is mentioned that witches in America turned children into food like hot dogs so that they were eaten by their own parents.
A Gerald Durrell story involves a French restaurant disposing of a critic's body by serving it to the customers. This leads to great reviews and a mention in influential travel guides (the very reason why the critic was invited in the first place)
Steven Erikson's Malazan Book of the Fallen has the Pannion Domin in the third book, Memories of Ice, a ghastly empire of cannibals. Their peasant horde, the Tenescowri, are part of the army and double as a food supply for the officers. In fact, humans are the only source of food the Pannions eat, so the Domin is completely dead in its core lands and only alive on the border, where there are other peoples to conquer and eat.
The Greek historian Herodotus writes about cannibalism a number of times. Perhaps most notably is the story a disgraced Persian officer being fed his son at a feast as punishment. Herodotus didn't think too well of Persian people, apparently.
Jonathan Swift's satirical pamphlet A Modest Proposal proposed solving the problem of the mass poverty and starvation in Ireland by selling the Irish children as a delicacy. He was really criticizing how little was currently being done for the Irish, but many readers thought he was seriously suggesting cannibalism. Some even agreed.
The children's book Baa! is the Soylent Green story WITH SHEEP!. No, seriously. Finding out that your lamb chop is made of sheep isn't quite so much of a big reveal, though.
The 'popular restaurant with a secret' version predates TV: attend for instance the tale of The String of Pearls, about a barber who murdered his customers and sold the bodies to the pie shop next door, a classic pennydreadful of Victorian days. And yes, his name was Sweeney Todd.
A front-page article in the Sunday Sport, possibly inspired by the Sweeney Todd story, involved a man killing a tramp and making his body into döner kebabs to sell at his takeaway.
For those who don't know, döner kebabs (normally, no relation to No Party Like a Donner Party) are a Turkish dish made of meat on a pita (like a gyro); they're a popular fast food in some areas, especially Germany.
In the short story Babycakes, Neil Gaiman (who eats meat and wears leather jackets - but assures us that he is "rather nice towards babies"), one day all the animals on earth disappeared mysteriously. From the title of the work, guess how humanity coped with this. Neil wrote this for PETA, but it's best not to think of it as a parable — it's far more enjoyable just as an exercise in creepiness.
Subverted in Neil's book American Gods, Mr Jacquel, a mortician and autopsist, eats small parts of the bodies he's working on, but "... somehow it seemed ... a good thing for him to do: respectful, not obscene." This is because Jacquel was the god Anubis, one of the Egyptian deities responsible for judgment after death.
Similarly to Babycakes, Meat by Joseph D'Lacey, a post-apocalyptic novel, lets us slowly realize that the 'cattle' are humans (apparently bred to be stupid and cow like). This is particularly gratuitous as the novel states that this only happened as the real farm animals almost died out and became too rare. Yet over the generations required to breed the human stock, farm animals with shorter generations and multiple births must have recovered their numbers.
Piers Anthony's novella The Barn was a similar concept, done marginally better: Most mammal species had become extinct.
Through Darkest America is an After the End novel with some similar themes to The Barn. In much of North America, animals other than humans are extinct. To allow meat production to a society mostly at about an 1800 technology level, they have "stock": They LOOK like humans, and are believed to be able to interbreed with humans (although there's a strong religious taboo against it), but they cannot speak so they must not have souls, so eating them isn't wrong. Then the hero finds out what happened to his little sister when she got to move to the government's claimed reconstructed area…
Red Lotus by Pai Kit Fai has the confectionery mu-nai-yi (mellified man) made by steeping a corpse in a casket of honey for a hundred years.
In Have Space Suit – Will Travel the aliens nicknamed "Wormfaces" kill and eat captives that they no longer have any use for. Kip and Peewee are kept alive as possible hostages but Jock and Timothy, cellmates of Kip both disappear and are assumed to have ended up in the stew pot.
In Stranger in a Strange Land, we see one of the relatively rare subversions of the trope, with Valentine Michael Smith encouraging a literal interpretation of the biblical phrase "This is my body..." This is because Michael was raised by Martians, who routinely practice funereal cannibalism to "grok" the essence of the departed, as well as not let organic matter go to waste on a resource-poor world.
At one point a character asks Michael if he "feels like dinner". Growing up as he did among the Martians, Michael had always been aware that he was food, but wasn't expecting to be called upon him to take that role so soon. He's a little surprised and disappointed, but is explicitly still willing to make the sacrifice if it's necessary. However, she explains quickly enough to prevent him from doing anything drastic.
In Leonard Wibberley's A Feast of Freedom, the islanders of Omo Levi kill and eat the Vice-President of the United States to expiate his sacrilege. The ensuing trial features an anthropologist giving a learned discourse on the history of cannibalism. Also, the original version of the Omo Lau national anthem, set to "Jesus Loves Me", really translates into English as "Lily skinned feller/From over the sea/I'll eat you/Or you'll eat me." (This refers not to Caucasians, but to the fairer-skinned Polynesians, chronically in conflict with the Melanesian islanders.)
In The Bad Place by Dean Koontz the bad guy drinks the blood of his victims. His sisters dug up their dead mother and ate some of it and shared the rest with their mob of cats - so their mother 'would always be with them'.
In C. S. Lewis's The Silver Chair, the adventurers are visiting the Giants and happily eating venison when Puddleglum tells them to stop eating; the Giants' conversation has revealed that this was a talking deer. Any sapient animal eating another is committing the equivalent of cannibalism.
Their initial reaction to the realisation varies, however: of the three of them, Jill, visiting Narnia for the first time, "felt sorry for the poor stag and thought it rotten of the giants to have killed him", Eustace, making his second visit, "felt horrified, as you might feel about a murder", and Puddleglum "who was Narnian-born, felt sick and faint, as you might feel if you'd...eaten a baby."
They later discover that the giants are planning to eat them as well, after finding recipes for human and marshwiggle in the kitchen.
In "The Picture in the House", the protagonist meets a creepy old man who's fascinated by historical accounts of cannibalism. It gradually dawns on him that the man's interest in the subject is not purely theoretical.
"The Rats in the Walls" dealt with this trope as well, in a truly horrifying way. Subterranean stables full of degenerate humans bred for their meat are involved.
August Derleth added the Tcho-Tcho to the Cthulhu Mythos, a Burmese tribe of pygmies that worships ancient and malevolent gods. By their D20 Call of Cthulhu entry, the Tcho-Tcho have integrated in American society, and tend to operate popular restaurants serving dishes with delicious human ganglia paste... er, "White Pork Sauce."
Sabina Murray's A Carnivore's Inquiry. The narrator turns out to have been eating her way across the country. (So to speak.)
The Dawn of Dragons trilogy from Dragons of Requiem has the Widejaw tribe. They're barbarians who Rape, Pillage, and Burn, drink blood from skulls, and tend to feast upon the flesh of their fallen victims.
In the Tim Powers novel The Anubis Gates, the head of a secret society of beggars turns down a dinner invitation at a rival society, saying that he doesn't care for the variety of pork they serve.
Nation, First Mate Cox becomes chief of a tribe of cannibals, though he insists he had the fish. Not that he would have mind. He only stated that as a matter of, you know, 'class'.
In Monstrous Regiment, also by Pratchett, we are introduced to 'Threeparts' Scallot, the three parts in question being one arm and both legs, at least one of which was eaten by a fellow soldier while snowed up on campaign. But fair's fair, Scallot ate his. Well it's not on, is it, eating your own leg? You'd probably go blind.
Upton Sinclair's book The Jungle described the manufacture of "Durham's Pure Leaf Lard;" workers who fell into the vat were processed along with the rest of the meat. This was the only one of Sinclair's claims about the meat packing industry that wasn't verified later by the FDA. That doesn't mean it wasn't happening — the factories knew they were going to be inspected.
Hannibal Lecter: Dr. Hannibal "the Cannibal" Lecter. Not only a cannibal, but a gourmet cannibal.
In Hannibal Rising, Thomas Harris expands on Hannibal's history, including his childhood and being orphaned in Lithuania. Nazi deserters take up residence in his home and force him to watch them kill and cannibalize his sister Mischa, sparking his obsession.
Hannibal also drugged and breaking speeched nemesis and main villain Mason Verger into cutting off his own face and feeding it to his dogs, during which he eats his own nose. It is implied Mason had previously allowed industrial accidents to go overlooked in his meatpacking plant, exposing the market to trace amounts of his workers' flesh. Mason also took bites from his sister's buttocks while sexually abusing her throughout their childhood.
In addition, Hannibal may very well have tricked others into eating human flesh; there's a strong possibility that he might have served parts of one of his victims to the directors of the Baltimore Philharmonic Orchestra. And then there's his seduction of Clarice into eating Krendler's brains...
In the book Fried Green Tomatoes at the Whistle Stop Cafe and film, an elderly woman kills a man in self defense. He had it coming. Knowing it would be impossible for her to get a fair trial, the protagonists get rid of the body by secretly cooking it and serving it as pork in the cafe. Doesn't sound that bad until you realize they served human flesh to their unknowing family and friends. On the other hand Curtis Smoote, one of the officers who investigates the disappearance, had a daughter whose life was ruined by Frank. He unwittingly gets his revenge by eating several sandwiches while in Whistle Stop.
The set of the movie has since been turned into an actual resturant called the Whistle Stop. What is particularly disturbing is that none of the patrons seem to be bothered by the connection to the pork sandwiches they were hungrily devouring. DIDN'T ANY OF YOU WATCH THE MOVIE????
Subverted in the book Bodyguard of Lighting by Stan Nicholls, The medic in a group of Orcs (ironically the protagonists) who are incredibly short of supplies, serves a hearty meat stew to a warrior who has just had his leg amputated. The rest of the orcs complain until they realise where the meat came from...
In Romance of the Three Kingdoms, Liu Bei is travelling and must stop to rest at the house of a man in the forest. The man, having no meat to serve to him, panics - he kills his wife and serves her to Liu Bei. The next morning, Liu Bei discovers the remains of her body, and figures out what he'd eaten the night before. However, instead of being squicked, he weeps for the man's loss, telling him that he'd have been happy with a simple plate of rice. He later relates the story to Cao Cao, who also weeps, and orders that the man be compensated for his loss! A bit of Values Dissonance going on.
Also in the novel, Xiahou Dun, after being shot in the eye with an arrow, utters the infamous lines: "Essence of my father, blood of my mother, I cannot throw this away," right before eating his eye.
In Outlaws of the Marsh, Sun the Witch and Zhang the Vegetable Gardener own an inn wherein they capture unwary travelers and cook them into dumplings.
In Richard Coeur de Lion, a Middle English verse romance based loosely on the life of King Richard I, Richard falls ill while on crusade and claims he won't get better unless he tastes pork. As he is in the Muslim-held Holy Land at the time, there is no pork to be found...so Richard's men kill one of their prisoners and feed his flesh to the king. Richard goes on to serve roasted "Saracen" heads to a party of terrified Muslim messengers, who watch in horror as the king first happily tucks in, then announces that the Christians will not leave the Holy Land until they have eaten all the Muslims. The poet, by the way, is completely on Richard's side here.
In H. G. Wells' The Time Machine, the Time Traveller goes 800,000 years into the future, where he discovers two main humanoid species: the Eloi, a group of attractive, youthful people living in an Eden-like paradise without a care in the world, and the Morlocks, a subterranean race of animalistic, fur-covered monsters that do all the work to keep the Eloi contented. It's revealed to the reader and the Time Traveller that not only are the Morlocks actually raising the Eloi for food, but both evolved from our own species. So it turns out that it's a satire on the class system.
In the related Emberverse series by the same author, after the Change, large groups of cannibals, called "Eaters", pop up in response to lack of food. They take the first book's place as the zombie horde in some parts.
In Ahab's Wife, Una is shipwrecked and fed the flesh of her captain by her shipmates.
Two Bottles Of Relish. Yum-Yummo is not very good on salads.
In The Hobbit, Gollum intends to eat Bilbo if he wins the riddle contest (and tries to even after he loses); The Lord of the Rings reveals that Gollum was one of "the river folk," who bear biological and cultural differences to hobbits, but either way it's close enough to count as cannibalism.
In The Return of the King, Saruman suggests that Gríma may have eaten Lotho Sackville-Baggins ("Buried him, I hope; though Worm has been very hungry lately.").
One notable aversion involves the orcs: Amusingly enough, the one thing they won't stoop to is eating other orcs (humans, though, are fair game). They changed this in the movie ("Looks like meat's back on the menu, boys!").
In The Vampire Chronicles, Maharet and Mekare's people routinely roast and eat their dead as a properly respectful funeral. It's eventually used as an excuse to destroy the tribe and kidnap the twins.
In the book, Queen of the Damned, Mekare eats Queen Akasha's heart and brain. This is not what happens in the movie.
The protagonist of Succulent Prey by Wrath James White struggles with and eventually gives in to overwhelming cannibalistic urges which are the result of a contagious infection he suspects he caught from the blood-drinking child rapist/murderer who kidnapped him as a child.
In Cormac McCarthy's The Road, almost all life has been destroyed in an unseen apocalypse. So you can guess what the bad guys eat — and what they eventually store, and raise, and hoard — for food. It will redefine your view of Black Comedy, that's for sure.
Charles Dickens wrote a little-known short story called Captain Murderer which was about a pirate who would not only have his wives cooked into meat pies, but actually force them to roll out the crusts themselves before chopping off their heads and cutting them to bits. Eventually one of his sisters-in-law finds out. She convinces him to marry her, and before he decapitates her and has her baked into pie, she secretly consumes a deadly poison. He dies immediately after devouring her remains.
Taken to the extreme in Stephen King's "Survivor Type", about a drug-smuggling surgeon who gets stranded on a tiny island with nothing to eat but himself, one amputation at a time.
"lady fingers they taste like lady fingers"
Cannibalism was also supposed to be the subject of The Survivors, a novel King was planning about the inhabitants of a high rise who get trapped inside due to a disaster and turn to one another for food. He felt he couldn't find a way to write it without seeming goofy, however, so it's been shelved since the Eighties.
The orcs from Grunts!! will happily eat other orcs, even going so far as to refer to the wounded as "field rations". There is also a memorable passage when Ashnak is served up a haunch of roast halfling while imprisoned.
Will and Ned Brandiman, the morally flexible at best halfling thieves hired by the Nameless Necromancer, are more than prepared to eat human flesh in order to divert suspicion away from them when murdering.
Friday's people (and their enemies) in Robinson Crusoe are cannibalistic Carib Indians.
Terry Goodkind's Sword of Truth series includes a primitive tribe called the Mud People, which practices cannibalism. Our hero, Richard, is obliged to partake as part of a ritual to prepare for communicating with spirits (though it's his choice to do so — the Mud People don't force their practices on others). He is served this special dish three times during the books, each time it's enemies. Appparently, the Mud People mainly eat their fallen enemies, and sometimes gain mystical insights into them by doing so (Richard does once). Richard learns of this when he asks what kind of meat they're serving, and he's told it's 'fire fighter' (apparently, he already suspected what it was). When he asks what that is, they explain it's the Big Bad's servant, demanding them to follow the law forbidding fire. They decided to prevent him from bringing any more enforcers.
Brazilian novel A Droga do Amor had an Evil Genius trying to escape a high-security prison by taking the place of a fellow elder prisoner which would be transferred. After studying the guy and creating a disguise, he killed the old man, cut him into pieces and bribed the prisoners in the kitchen to put said pieces in the ground meat. A detective then drops his sandwich and goes to the toilet - leading the prison warden to say in the bathroom door that the sandwiches didn't have such an ingredient...
Mark Twain once wrote the short story, "Cannibalism In The Cars", about a group of politicians whose train was snowed in. They decided who among them would be dinner via normal political debate.
Subverted in one of the Danny Dunn children's books, when the heroes are stranded on a small Pacific island. One of them gets lost, and the others follow his trail, to find what looks like a cliche "boil the missionaries" scene in progress: the missing friend is sitting in a big black cauldron over a bonfire, surrounded by natives. Before they launch an attack to rescue their companion, Danny has a Fridge Logic moment, realizing that if the locals really wanted to eat somebody, they'd have killed and butchered their victim before cooking him. In truth, the missing friend had fallen into some extremely stinky mud before being rescued by friendly natives, and is taking a bath in the heated water of the cauldron.
The Fuller Memorandum, by Charles Stross, features a rather disturbing bit where the protagonist Bob is kidnapped by cultists who cut strips of flesh from his arm to eat, with truly demented gaiety.
Julian:"Anyone for sashimi?"
Jonquil:"Nom nom nom! Chewy!"
The Gone series. In book 1, the trapped kids worry about what will happen when the food runs out. In book 2, the food does run out, and some kids are seen wondering what human flesh would taste like. In book 3, the Perdido Beach kids have (sort of) solved their hunger problems by learning to live off the land, but the Coates kids are litterally starving to death. When one kid commits suicide, the others are forced to eat his body to keep from starving. Caine struggles with the temptation to eat before eventually giving in, and Diana later expresses disgust and regret at what they did, but Bug seems perfectly okay with the idea and it's indicated that the others are too desperate to care.
Partially subverted in the Codex Alera series, the Marat race eat their enemies to "partake of their strength", but unlike the usual examples they aren't portrayed as being evil, except in part of the first book, before we get to see them in some detail, and in fact, The Hero ends up married to one in the end. A more antagonistic faction portrayed as "evil" or "deviated" is shown eating their captives alive.
The villains of the aptly named novel Dexter is Delicious kill, cook and eat their victims. Not necessarily in that order.
Tadeusz Borowski's short story "The Supper" focuses on concentration camp inmates who've just spent a whole day at hard labor with no food. Twenty inmates are accused of conspiracy, so the camp commandant has them all shot in the head, and leaves their bodies lying around as a warning to the others. As further punishment, he denies the entire camp dinner—but the moment he's out of sight, every inmate rushes for the still-warm meat on the ground. (The author assures us that raw brains go down surprisingly easily.)
Robin Jarvis's Intrigues of the Reflected Realm, which has of this writing only volume, features a world where there are no living animals, only clockwork devices. Some of them "eat" plants, which produces a mulch that grows with a fungus inside them to produce a meat substitute. One particularly nasty character makes reference to a place where apparently the residents decided to see how this compared to the real thing.
In the short story collection A Banquet for Hungry Ghosts, an innkeeper during the time the Great Wall was being built made dumplings out of human flesh. Even while everyone was wondering how he kept making such delicious, meaty dumplings when even the richest people in the village were starving, no one thought to connect it with the fact the men working on the wall were sporadically disappearing. Later, after the innkeeper is eaten by rats and turned into a hungry ghost, he does this to the arrogant new owner of the inn after the new owner puts out weed-paste dumplings for the ghost instead of meat. The villagers like to say that since he didn't like the taste of the dumplings given him, he made his own.
Donald Kingsbury's classic SF novel Courtship Rite features a Lost Colony where desperation in the face of poor harvests has made cannibalism socially acceptable over the course of many centuries. The degree to which it's accepted varies between nations and clans. Killing people just for their meat when there's no famine is generally frowned on, but funerals are always an opportunity for a feast.
The Rat Cook is a mythological figure who murdered a man's sons and fed them to him in a pie. He was transformed into a rat by the gods in punishment - not for the act itself, but because he violated Sacred Hospitality while killing them when they were his guests.
Lord Manderly probably emulates this with three Freys, who "disappear" shortly after leaving his domain, shortly before Manderly serves up three huge pies as a wedding feast for Ramsay Bolton. He even takes two slices of each pie for himself. He is of course suspected of having murdered the Freys (almost certainly true but even this is unprovable in-book), although nobody in-book suspects him of eating them, even though he had his bard play the song of the Rat Cook at the wedding - and personally cuts the portions to serve to the Boltons and Freys. In any case he waited before murdering them until they were no longer his guests. That would be hypocritical after all, as he hates the Freys because they murdered his king and son while they were their guests.
Subverted when Arya realizes while eating that she doesn't know what what they do with the bodies at the temple and stares at her fork in horror, but is assured that it's just pork. As it turns out, what they do with the bodies is cut off their faces and store them so they can magically use them as disguises for assassination. Which isn't much better really.
The unspeaking animalistic man just called Biter eats people, and has filed his teeth to help with this. He's known to do it during fights too.
The Isle of Skagos is believed to be filled with Cannibal Clans, though how true this is hasn't been seen yet.
The Undying warlocks attempt to devour Danaerys, and are only preventing by her dragon igniting the enormous disembodied rotten beating heart keeping them alive.
Gregor Clegane inflicts this on Vargo Hoat by cutting off the man's limbs and feeding them to him.
Similarly, the Tattered Prince once cut off the foot of a man who deserted from Tatters' mercenary company on the ground that the food was bad, roasted it, and forced the deserter to eat it. Then he made the man the company cook.
Subverted with the giants, who according to legend feast on human flesh, but turn out to be vegetarian. Not that this makes them less dangerous.
There's also the "bowls of brown" served in the poorer quarters of King's Landing. In A Storm of Swords, Tyrion talks Bronn into making a troublesome bard disappear, and Bronn says he'll likely end up as stew.
In A Dance With Dragons, Coldhands provides Bran and co, who are starving with some nice roasted pork. Pork from pigs Coldhands somehow managed to find in the middle of a barren, snowy forest, and which coincidentally turned up shortly after Coldhands killed some Night Watch deserters. The more benign explanation is that the pigs, like the deserters, were escaping from the remains of Craster's nearby outpost after the Night Watch mutiny.
Euron Greyjoy captured the warlocks of Qarth, who had been attempting to find Daenerys, and murdered one of them and forced the others to eat him as a means of breaking their spirit. As he says it,"Man is meat."
In the Congo novel, the team has to constantly avoid a cannibalistic tribe of natives who are at war with the Mobutu government. Partly because they were cannibals, but mostly because Mobutu was a vicious dictator running a People's Republic of Tyranny and he didn't like that said tribe was ignoring him.
Used to help establish the nature of Lolth in Queen Of The Demonweb Pits:
Lolth: I feel just like a little girl! Have the cook send one up!
In John Ringo's Legacy of the Aldenata series, the main baddies, The Posleen, fill this role very well. Not only do they have one word for species other than themselves or the Aldenata(whom they call the Aldenat and worshipped as gods), but that one word is the same for food, thresh. They had to create a new name for humans, threshkreen, which translates out to "food with a stinger". These Posleen can and do eat anything, such as: natural flora and fauna, any other sentient race, humans, each other, their young...
This comes up in the second book of the Council Wars series. Humans have the ability to Change themselves into any form they wish including mythical creatures and sentient animals. The Heroes are organizing a fighting retreat along with Mer-people, Dolphionos (humans Changed into Dolphins) and Dragons (who are not changed humans). Due to short supplies they end up eating their opponents (humans who are Changed into either Orcas or a sort of Manta-Ray like creature). Interestingly they don't seem particularly bothered by this other than a single exchange noting that while it is technically cannibalism the Orcas were eating the Mer-people first so they started it.
Repeatedly in Tales from the Mos Eisley Cantina. Wuher (the bartender in A New Hope) brews the remains of Greedo into a strong drink that he hopes will gain Jabba's favor. A human thief once broke into the Devaronian Labria's apartment, and it turns out "humans don't taste very good." Finally, the only meat that H'nemthe females eat is the flesh of their sexual partners.
There are a few sentients who will eat sentients in Galaxy of Fear, though in Eaten Alive and Army of Terror it's borderline To Serve Man. The last book, The Hunger, features the descendants of a team stranded on Dagobah for years. Some had children, and the edible fungus their parents scrounged wasn't enough. Unusually, the Children are portrayed as sympathetic, pitiable, even after they kill and eat someone. They try to help - and feed - the visiting protagonists, and are shown visions of their past.
The last vision was terrible. Zak saw the survivors, starved into madness, turning on a corpse. He and Galt and the other Children could clearly see how horrified the parents were by their own acts. What they had done was a last, desperate attempt to save their children. It was the act of beings so hungry they had lost their minds. As the parents fed their starving children, they cried.
The Children had relished the thought of eating human flesh because they remembered it from their childhood. But this vision had shown them how desperate their parents had been, and how horrible their final act really was.
Given an unusually sympathetic portrayal in Peadar Ó Guilín's novel The Inferior; the (human) main character's tribe traditionally eat their dead, and while characters from more 'civilised' communities are horrified, nowhere in the book is it treated as anything other than a pragmatic and respectful funerary custom.
Ringworld sequels have a race known as the Night People, who eat dead hominids. They're quite civilized about it, and meticulously apply any and all death-related rituals of a dead person's religion (if any) before chowing down. In the event of plague outbreaks, they will even help with constructing crematoria and teaching people how to use them to get rid of disease. Don't try cremation or burial unless they OK it first, though. They're rather possessive of their food supply.
In Last and First Men, it's revealed that the Last Men (a species descended from humanity over the course of millions of years) honor their dead by consuming their bodies with great ceremony—just to emphasize how different their culture is from ours.
The villain in the book Silverwing is a bat who feeds on other bats.
In Poul Anderson's "The Sharing of Flesh", the ship that finds a lost human colony discovers that all humans on it practice cannibalism. The computer discusses how it is taboo in all known cultures except sometimes to save lives, and historically may have been part of Human Sacrifice and magic — plus one culture that regarded it as just plain meat, which the British exterminated. Evalyth finds herself sympathetizing with the British.
In The Twits Mr. Twit has no qualms with the idea of making several boys into a pie.
In the novel A Nameless Witch, the titular character has the problem that the more she loves someone, the more she wants to gobble him down.
Bentley Little's short horror story "The Washingtonians" reveals this is the horrific hidden secret of George Washington; he gained a taste for human after being forced to eat the dead at Valley Forge, and it went downhill from there.
Journey to Chaos has a Downplayed Trope. Eric asks if he can eat another human but since he is technically a grendel at that point (albeit one in human form) it's technically not cannibalism. However, he still identifies as a human (at first) and so the idea repulses him.
Cannibalism is de rigeur for the inhabitants of the planet Sangre in Norman Spinrad's The Men in the Jungle. The ruling elite (The Brotherhood of Pain) dine on specially-raised human children (called "Meatanimals") culled from the peasantry, who are referred to - and refer to themselves - as "Animals." In order to become a member of the Brotherhood, the protagonist is forced to kill an infant and consume a piece of its flesh.
In the Dred Chronicles, the protagonist considers some inmates on the lawless Prison Ship Perdition to be this, though they themselves may not. Dred's gang and Mungo's gang both have access to machines which break down organic matter for re-use, and given the general lack of resources, "organic matter" includes corpses. Dred's people turn corpses into fertiliser for hydroponics, but Mungo lacks both hydroponics and any kind of squeamishness, so he turns corpses directly into steaming roasts. From a scientific perspective, the machines have transformed the matter too much for it to still be human meat in a biological sense, but Dred still finds the idea unacceptably creepy.
In The Sword-Edged Blonde, Queen Rhiannon stands accused of boiling and partly eating her own child as part of an occult ritual. Since she was found with a pot containing bones, was coughing up chunks of meat, and the baby was nowhere to be found, most people consider the case against her to be airtight, but her husband the King refuses to believe it. She didn't do it; someone just went to a lot of trouble to make it appear so.
In The Golgotha Series, the Skull of the First Murderer selects murderers to become its worshipers, and it particularly prefers those with a taste for cannibalism. Examples include Boyle "Liver-Eatin'" Douglass, Charles Cook, Nikos Vellas, and the Brechts.
In Urban Dragon, ghouls gradually adopt the traits of whatever animal proteins they eat, to the point where consuming pork or beef turns them into bestial monsters. The only way to keep their human appearance and intelligence is to eat human flesh.
In Watersong, the sirens captivate men with their song, then kill them and eat their hearts. They require a minimum of four hearts per year to stay healthy, but eating more increases their powers.
Jon Shannow is unlucky enough to come across two cases of this in quick succession in Wolf in Shadow. First he fights off a tribe of cannibals who file their teeth to points. Then later on, when he's going through the saddlebags of a Hellborn he's just killed, he finds some tasty-looking cuts of preserved meat. He's seconds away from having a bite when someone else tells him that the meat comes from child sacrifices. The Daggers and Beast-men from the sequel The Last Guardian also find humans rather tasty.
Bearheart: The pilgrims learn that the meal they shared with the priests was actually the flesh of one of the priests who died.
In Everybody Loves Large Chests the protagonist is a adventurer-eating dungeon mimic. While elves and dwarves are tasty, humans are always the creatures favorite.
Discussed in Seeker Bears. Two polar bears discuss a rumor that a recently-deceased mother named Nanuk ate her cubs after they had died. The elder bear ignores the rumor, saying that Nanuk would have never done such a thing.
In The Hunger Games, Katniss describes how a boy named Titus, who was a tribute in a previous Hunger Games, went mad and ate (or tried to eat) his fellow tributes after he had killed them. Though there are technically no restrictions on what the tributes may do to each other once the Games have begun, even the audience in the Capitol (who normally have no problem watching kids kill each other) drew the line at cannibalism. As a result, most of Titus's kills were censored and he often had to be stunned to enable the Gamemakers to collect the bodies of his victims. When he was eventually killed by an avalanche, many people suspected that the Gamemakers had set it off deliberately to make sure he didn't win.
Count Ugolino may have only eaten the corpses of his children out of desperation, but once he's damned for treason, he is reduced to eating the odd off another traitor for no other reason than pure hatred. This sickening "relationship" shows what humanity becomes the farther they are from God and foreshadows the monstrosity of Lucifer.
Just after he talks to Ugolino, Dante finds Lucifer reduced to a screaming monster, whose only solace is in shredding Judas, Brutus, and Cassius apart with his three mouths. Unlike Ugolino, the Devil can't even talk and consumes the entirety of his victims instead of just their heads, showing that he is the "perfection" of the evil that was seen in the cannibal count.