Nemu Kurotsuchi, Mayuri Kurotsuchi's servant in Bleach, though she lacks many of the physical traits specified above and calls Mayuri by his name with a -sama honorific (which is often used by servants to their masters).
Toad plays the Igor role to Magneto in early X-Men comics.
In Little Gloomy, Mad Scientist and jilted boyfriend Simon von Simon employs the hunchback Boris as his assistant. Boris, however, bears no real allegiance to Simon and only works for him because, as a hunchback, he doesn't have any other job opportunities. Boris is also somewhat explicitly much more sensible if not in fact smarter than Simon.
Grimer from Sonic the Comic is an exemplary Mad Doctor's Assistant to Big Bad Dr. Robotnik. As well as the usual Igor traits (hideous goblin-like appearance, frail build, intense loyalty, referring to his boss as "Master", etc) he was also something of a Hypercompetent Sidekick, being the primary designer of many of Robotnik's most dangerous war machines and personally coming to Robotnik's rescue on several occasions. His finest moment came when he was jailed after Robotnik was apparently destroyed by the Chaos Emeralds, where he proved he was a manipulativeChess Master and managed to manipulate the heroes easily from his prison and save his master.
The American Sonic the Hedgehog comics had Snively in this role during his early appearances. He's still a toady nowadays, but after 16 years he's grown to hate his job a bit. Sniv has come to rely on being a Deadpan Snarker as his chief coping mechanism. It seems to work decently enough.
Gina from Gold Digger teases her sister Britanny by referring to her as her Igor.
Batman, of all people, actually had a mute hunchback assistant for a while in the '90s. Harold Allnut was a gifted mechanic and electronics technician who helped out in the Batcave.
Godland features Eghad, the simple assistant to criminal mastermind Friedrich Nickelhead. Eghad's intelligence is extremely lacking, and he knows little but undying loyalty to his master. Unusually for this trope, he's also Nickelhead's bodyguard and packs a frankly ridiculous amount of power in his tiny frame. Also somewhat uniquely, Nickelhead isn't cruel to Eghad.
Vincent Frankenstein in The Frankenstein Monster has a hunchbacked servant named Igor. However, in this instance Igor is also a brute who is almost as tall and strong as The Monster.
Both films of Count Yorga had Brudah, a deformed shambling man who serves as the Count extremely tough servant. He has been showed to defy his master once though in the first movie, where he rapes the damsel after Yorga controls her to come to his mansion during the daytime. He is later seen shameful of the act and begs Yorga to forgive him.
Dracula of The Monster Squad tries to use Frankenstein's Monster as one of these, ordering him to retrieve Van Helsing's diary. He's quickly won over by Phoebe, the youngest of the eponymous crew, and turns against his master.
Back to the Future's Marty McFly meets the "short, loyal lab assistant to a Mad Scientist" criteria, but is a reasonably well-adjusted teenager whose relationship with the Doc is less "subservient toady" and more "frequent rescuer of his Big Brother Mentor."
The butler and maid from Transylvania 6-5000 were both hunchbacks, and a married couple whose son had an even more extreme hunch. Or so it seemed; really, all three of them were faking to conform to this trope's groveling-hunchbacked-servant expectations.
Krull of Mr. Sardonicus is more well-spoken and normal looking than your typical Igor, but is still a good fit. He's Sardonicus' main servant/doer of dirty work, and has a deformity in having an eye missing (because Sardonicus ripped it out). While Sardonicus is the more villainous of the two, Krull is shown to be fairly sadistic himself, and ultimately gets revenge in a cruel The Dog Bites Back moment.
Cojo the midget plays this role to Alonzo the Armless in The Unknown.
Terry Pratchett's Discworld distills the trope by featuring a clan of these types, all named Igor (except female Igors, who are named Igora or Igorina). They all have their own unique pattern of scars and deformities (except for the female Igors, who are oddly enough very attractive, although they usually keep a stitch somewhere as a sign), and all of them incredibly skilled surgeons, chemists and inventors. When they work for Vampires, Werewolves and Mad Scientists, they often double as a butler. They also have a tendency to replace parts of their own bodies with bits from other people which are no longer in use by their former owners. Often an Igor will accept as payment for a surgery a promise that they can help themselves to the patient's body (for themselves and other patients) when they eventually die — a promise they take very seriously. They also hand down useful organs; when an Igor says "I have my grandfather's hands", he is NOT being metaphorical.
Furthermore, they rarely have any qualms about who they work for — they don't work for Vampires and Werewolves and Mad Scientists because Evil Feels Good, but because "Insanity gets the job done." An Igor would never do to another living person something that they wouldn't be willing to try first on themselves, though that doesn't necessarily narrow it down much. Even (relatively) sane and non-evil organisations (such as the Ankh-Morpork City Watch, The Free Hospital and a bank) recognise the value of an Igor and employ one or more.
Igors of Discworld are eerily good at:
Creating the essential and mandatory Cobweb Jungle using trained and specially bred spiders, urged on with very small whips.
Turning up behind you when you need them but don't expect them. (This might be a tribute to Eye-gor from Young Frankenstein, who went from the roof to right behind Dr. Frankenstein in less than a second.)
Opening the door exactly as you're raising your hand to knock. Relatedly, every door opened by an Igor will creak, whether or not it normally does. It's said to be a "skill".
Lisping, although this is done deliberately; "modern" Igors sometimes "forget to lisp." On one occasion, before delivering a somewhat longwinded explanation, the Igor in question asked if he could drop the lisp, to make said explanation easier to understand. (Later, another Uberwalder expresses concern when the Igor forgets to lisp, something that usually isn't done.)
Surgery — in particular, they can re-attach lost limbs and perform transplants using only needle and thread, and also possess the ability to completely suppress the patient's immune system incompatibility with the donor organ through means unexplained. They also have the ability to bring back people who have actually died, if it's recent enough (and if they're allowed to — dwarves in particular will not allow Igors to bring them back. Igors are said to be "naturally disappointed" by this). As of Unseen Academicals, Lord Vetinari has been compelled to make a law about this, because murder trials have a tendency to go wrong when the (formerly) deceased walks through the door: "If it takes an Igor to bring you back, you were dead. Briefly dead, it's true, which is why the murderer will be briefly hanged."
"Acquiring" materials for their master's latest deranged scheme.
They are also said to be quite popular with the ladies, despite their looks. We leave the reason for that to your imagination...
The motto of the Igors is "What goes around comes around" referring to both their habit of recycling body parts so much and so often and also their karmic approach to treatments. When an Igor gives treatment he expects that later he can come back and claim any strong organs that person has which might be able to help someone else (they tend to have waiting lists) but sometimes people get unnerved when an Igor shows up at their death bed look rather patient and refuse to let him have their organs when they die. The Igor accepts this and leaves. And doesn't ever come back to that village. Nor does any other Igor. What goes around comes around...
Interestingly, the Barman at Biers is named Igor, but is not a member of the clan — it's just a coincidence, which is odd as Biers is frequented mostly by the undead. He apparently finds comments about the incongruity of this rather irritating.
In Slipping Between Worlds the suggestion is made that in keeping with the Discworld principle that everything has its opposite quality, Biers' Igor is in fact a Rogi - the polar opposite of Igor-ness, one who is incredibly skilled at dismantling a living body, but not so hot at re-assembling it again afterwards.
Subverted in James Blaylock's Homunculus, where the hunchback creeping around the spooky laboratory actually is the Mad Scientist, Ignacio Narbondo.
In the Dragaera series, Sethra Lavode's servant Tukko/Chaz (his full name is Dri'Chazik a Tukknaro) comes across as a parody/subversion of this. In the Vlad series, he's described as constantly shaking and walking with a pronounced stoop, but Vlad suspects that this is Obfuscating Stupidity because despite his seeming infirmity, he never spills food or drink. This reading is supported in the prequel books in which he is revealed to be a famous wizard.
In the Star Wars Expanded Universe, Onimi is the Igor to Supreme Overlord Shimrra, the leader of the Yuuzhan Vong. The very last book reveals however, that Onimi is actually the mastermind behind the Yuuzhan Vong invasion and that Shimrra was actually a puppet being telepathically controlled by Onimi.
The original Reek, the servant to Ramsay Snow (later Bolton) from A Song of Ice and Fire. After Reek was killed, Ramsay tried to break his captive Theon Greyjoy into becoming his replacement Igor.
Good Eats introduced the dungeon under AB's kitchen, wherein his toadying Dungeon Master (The Igor in all but name) supplies him with painful kitchen appliances, such as a steak cuber and tortilla press. Yes, it's a cooking show; it's just not a normal cooking show.
Parodied on SCTV with actor Woody Tobias, Jr., who actually was an ugly hunchback and thus was confined to this role (named "Bruno") as sidekick to 3-D filmmaker Dr. Tongue, who usually played Mad Scientist roles. Both were "serious" actors, to the point they attempted a remake of Midnight Cowboy in 3-D, but they didn't have much range...
Gilligan's Island did two episodes with mad scientist Boris Balinkoff; Both times he had an assistant named Igor, the first time played by a human, the second by a monkey. (Considering the things Balinkoff got up to, it's even possible they were the same character..)
Both Jesse and Gale act as Igors to "Heisenberg" on Breaking Bad.
Twisted in the Farscape episode "DNA Mad Scientist": the Mad Scientist NamTar's female Igor, Kornata, turns out to be the original scientist, who was disfigured and enslaved by her rebellious creation.
Get Smart. Max goes up against a KAOS Mad Scientist who's using electricity to raise people from the dead. He naturally has a disabled toady for an assistant...called Bruce.
The evil genius of Jonathan Coulton's "Skullcrusher Mountain" has his assistant Scarface, whose description is textbook Igor.
In the fan-made New World of Darkness gameline Genius The Transgression, Beholden fill this role. Beholden are otherwise ordinary people who see the world exactly as the Genius sees it and thus can handle Wonders without wrecking them, help build them, and do all sorts of dirty work for their masters. In fact, "Igor" is a slang term for a Beholden. It's not very pleasant being one. Beholden lose their ability to form any beliefs or meaningful opinions beyond copying those of a Genius, and if they're without a master for too long, they either go mad or die. They also have a tendency to experience a Breakthrough in certain conditions and become a Genius themselves.
Dr. Mordenheim is Ravenloft's Expy of Dr. Frankenstein, so naturally he has an Igor: a hunchback named Horg, whom he's re-created via cloning each time his assistant gets killed. Robbing graves in Ravenloft isn't the safest vocation, so he's on his third or fourth Horg by now.
An Igor (called "Egor") is the protagonist of the Amiga platform game Frankenstein. Your goal in the game is to bring the required ingredients to dr. Frankenstein so that he can create the Frankenstein's Monster.
At the start of Monster Lab, the player is given a PDA aptly named I.G.O.R.
Igor makes an appearance in Castlevania as an invincible fleaman that assists Frankenstein's monster in battle in the first game, thus subverting the usual idea that Igor doesn't participate in combat.
Another webcomic treatment: In the Girl Genius"The Coffee Engine is Broken?!?" storyline, Agatha finally makes it to her ancestral keep, only to find the entire TOWN surrounding it is populated with Igors subconsciously pining for their masters the Heterodynes... and woe betide pretenders that hang around instead of getting eaten by the Castle.
This is a thing with Sparks in general. When in the madness place, they tend to drag others along in their fervor, with those who are exposed long enough becoming highly conditioned to serve Sparks (not exclusive to their original master). One character suggests this is an evolved survival trait (As in, people who volunteer to be minions are much more likely to survive to breed than people who are selected to be test subjects. Apply this selection criteria on a community for fifty generations.).
And von Zinzer, Agatha's follower whose reluctance to fall into "minion" routine, while useful in itself, produces hilarious scenes.
In Narbonic, most respectable mad scientists have henchmen. It's just the way things are done. Dave even jokes that his boss should call him Igor◊. Later, the henchmen unionize.
The Cinema Snob noted in his review of The Body Shop that mad scientists in the movies he reviews always seem to have deformed sidekicks for no reason, and he wants to know how the assistant ended up with the doctor (at least one, Blood-Sucking Freaks, explains that Ralphus is just a sadist who does it for free.)
"Oh, of course he has a deformed sidekick. Where do these people like Frankenstein GET their deformed sidekicks? Do they just post up a Craigslist ad? Were humpbacked miniature servants really that good around the science lab? Seriously, all of these fucking mad doctors have them! From Doctor Frankenstein, all the way down to fucking Sardu! "
In a later review, he gives Z-grade movie Geek Maggot Bingo props for explaining how they met, which actually does show The Igor finding the job in a classified ad.
"Honestly, I will have to hand it to this movie - it does explain how the doctor and his hunchbacked sidekick meet. In The Body Shop, The Astro Zombies, or hell, even Bloodsucking Freaks, the duos just sort of already knew each other for some reason. This movie at least shows us their humble beginnings... and it still sucks."
Reboot: In later seasons, Mad Scientist "Herr Doktor" is Megabyte's top man. The doc has an unnamed assistant who is a heavily disfigured "one" binome.
In the Beast Wars episode "Feral Scream", Waspinator fills in the role of The Igor while Megatron is creating Transmetal 2 Dinobot. Waspinator even speaks lines such as "Yes, Master" in a creepy sort of voice.
Aladdin: The Series: Aside from being a magical flying eel, the evil sorcerer Mozenrath's sidekick Xerxes fits this trope.
In Jibber Jabber, several of the boys' fantasies involved Jibber as 'Dr. Jibberstein' with Jabber as his loyal hunchbacked assistant 'Jabgor'.
The blatantly named Urpgor of The Dreamstone is this to Zordrak. While most Urpneys are sniveling toadies, Urpgor is exceptionally unhinged and weasel-like, even refering to Zordrak as 'Master'. As a bonus he is the Mad Scientist of the Rogues Gallery.
Gargoyle in The Incredible Hulk who fits the role perfectly, he is ugly, short, has large head, and acts as an assistant to The Leader.
Averted in Count Duckula - Igor is Igor in name only in this instance and is a very capable, intelligent albeit sinister butler. Also, don't mess with his master or you will regret it.
The cringingly villainous sidekick, Harry Slime from Avenger Penguins fits this trope more closely, right down to the Peter Lorre accent.