The Albert Finney musical version of A Christmas Carol, Scrooge, has "I Hate People" for the title character, which should be self-explanatory, and later, the toe-tappingly nasty "Thank You Very Much", in which everyone who owes Scrooge money gloats over his death in the Bad Future. The latter song gets a light reprise upon Scrooge's redemption.
Several Beatles classics became Villain Songs in the movie Sergeant Pepper's Lonely Hearts Club Band. The actual quality of the musical interpretations are a mixed bag. The treatment given to "Maxwell's Silver Hammer" by Steve Martin is best forgotten, as is a version of "Mean Mr. Mustard" sung by robots. On the other hand, Aerosmith's version of "Come Together" has outlived this movie and become one of their signature songs.
"Main Hoon Don" from the Bollywood movie Don; in a twist, it's sung by someone who has to impersonate the villain. Or so we thought.
Veruca Salt's destructive "I Want It Now" number in Willy Wonka and the Chocolate Factory, the last musical number not sung by the Oompa Loompas, possibly because they were too busy at the moment trying to stop her. It also doubles as (yep...) an "I Want" Song, after a fashion.
Lyricist Leslie Bricusse helped adapt the film into a stage play for regional theatres and gave each of the other brats a song as well, which aren't as mean but certainly sum up their vices: "I Eat More" for Augustus, "Chew It" for Violet, and "I See It All on TV" for Mike.
Although he doesn't sing it himself, Necros, The Dragon from the Bond film The Living Daylights gets a thoroughly Bad AssVillain Song called, "Where Has Everybody Gone?" It's always playing on his Walkman when he's about to strangle people with the headphone wires. And his Leitmotif is the instrumental version of the song. The song fulfills the criteria of the Villain Song, in that while the Big Bad is a fairly low-key Smug Snake, Necros is the main physical danger to Bond throughout the movie, manages to get away with a surprising amount of successful assassinations for a Bond Villain, and gets a spectacular, over-the-top final fight/death scene.
It only makes it onto the soundtrack, but since it's a particular character's theme, it still counts: "Turkish Delight", a G-Rated Drug addict's lament sung from a tweaked-out Edmund's point of view, is by far the best song on The Chronicles of Narnia soundtrack. (How much of a villain Edmund is is, granted, questionable, but he's still the most villainous of the Pevensie kids.)
Highlander: The Kurgan has a theme song entitled Gimme The Prize, but only part of it is heard during the movie.
Likewise, the rendition of "New York, New York", which transitions from The Kurgan singing it in character to the soundtrack of Freddie Mercury hamming it up in equally raucous style. Sadly the only track Queen performed specifically for the film that has yet to be officially released in full length.
A song cut from the original musical, "I Found A Hobby", counts. The human villain basically describes how he discovered he was a sadist.
The Rocky Horror Picture Show has two: "Sweet Transvestite" and "You'd Better Wise Up, Janet Weiss (SLUT!)". Which makes sense, since the evil Dr. Frank-N-Furter is much more important than the hero Brad Majors (ASSHOLE!)
Three, actually— "I Can Make You A Man/Charles Atlas Song" is all about what he plans to do with Rocky.
Actually, "Sweet Transvestite" is more like an I Am Song, while "I Can Make You a Man" is an "I Want" Song. The only villain song in the movie is "You Better Wise Up, Janet Weiss!".
"World War II Boy" from The Blood Waters of Dr. Z, sung by an offscreen Jamie DeFrates as the Mad Scientist walks back to his lab from the beach at the beginning of the film. Only counts if you interpret the lyrics to be about escaped Nazi scientist Doctor Leopold and him "planning re-veenge on [his] friends!''
The movie version of The Little Prince has "A Snake in the Grass". And with Bob Fosse playing the Snake, the choreography is definitely show-stopping.
Following the Rule of Funny, this turns up at the end of The Fiendish Plot of Dr. Fu Manchu, an otherwise non-musical Affectionate Parody that presents him as a likable Villain Protagonist played by Peter Sellers. Not only does he succeed in his quest to create the elixir he needs to regain his youth and strength, he then unleashes his master plan for world domination: rock music. (The film is set in the 1930s.) The finale has him performing in full Vegas-era Elvis style garb "Rock-A-Fu", a distinctly early-1980s tune that gets both the goodies and baddies dancing, and forces Nayland Smith (also Sellers) to admit that at last, Fu's won.
"The Witch Is In The House" by the Wicked Witch of the West in The Muppets' Wizard of Oz. Miss Piggy nearly outdoes Curry's performance in Treasure Island. (Jokes about Piggy being a Large Ham are obvious, but if you make them she will hunt you down.)
Repo! The Genetic Opera has Gold for Rotti Largo. Mark It Up showcases the villainous Luigi and Pavi, but isn't as much of a showstopper as the others, so it only sort of fits this trope—especially because they're only trying to one-up each other and probably don't even consider themselves that bad.
Rotti also gets Things You See in a Graveyard, complete with plenty of gloating and cackling.
The Repo Man has "Thankless Job". It's Anthony Stewart Head with a voice like Christian Bale gargling broken glass, dancing and twirling away as he sings about organ theft, then gutting a person and using him as a human glove puppet... TO JOIN IN WITH THE SONG.
Arguably also "We Started This Op'ra Sh*t" for GeneCo as a company; it's certainly the most scenery-chewing number in the film, and features Rotti, Luigi, Pavi, and various GeneCo employees and customers generally hamming it up.
In the film Troll a song called "Cantos Profane" is performed by Torok the troll's minions.
Despite being a very low-level and banal form of evil, Sharpay and Ryan get one in each of the three High School Musicals, but it's only in the third one where "I Want It All",' is one of the big show-stopping numbers.
And some people prefer these upbeat songs to the ballad-y ones by the protagonists.
While more Grouch than villain, Oscar sings the "Grouch Anthem" at the beginning of the movie Follow That Bird: "Don't let the sunshine spoil your rain! Just stand up and complain!"
In both the film of Pink Floyd's The Wall and the album that inspired it, the three songs in the third act sung by the fictional Pink's fascist persona: "In the Flesh", "Run Like Hell" and "Waiting for the Worms". In addition to being a comment on the stupidity of fascism and bigotry, using holocaust imagery to show just how far our protagonist has fallen, they are also over-the-top villain songs sung with a sense of insane glee with some of the catchier melody-lyric parings (to the point that you start singing a split-second before realizing that some of the lyrics aren't for polite society).
In the sci-fi parody The Creature Wasn't Nice (AKA Spaceship), the titular monster stops his rampage long enough to sing a little ditty entitled "I Want To Eat Your Face".
In the early Adam Sandler movie Going Overboard, General Noriega briefly sings "It's A Sad Sad World When Your Head Looks Like A Pizza". Yes.
In Scott Pilgrim Vs The World, Matthew Patel gets the Bollywood-esque "Slick". It's also the only musical number in the entire film and has the cast gaping in confusion as he performs it.
The antagonists of both Camp Rock movies tend to have better (or maybe just catchier) songs than the protagonists.
The Gremlins in Gremlins 2: The New Batch organize their own rendition of "New York, New York" with the Brain as lead vocals.
The Golan/Globus production of Red Riding Hood had two. The Big Bad Wolf gets "Good at Being Bad". The wicked duke (It Makes Sense in Context) gets "Man Without a Heart".
In the So Bad, It's Good movie musical The Apple, corrupt music executive\Louis Cypher Mr. Boogalow gets a couple of musical numbers. "How To Be A Master" is the one that most fits the definition of a villain song thematically, since it has him extensively bragging about how successful being evil has made him ("Reaching the top is such a long, hard climb/Millions of people stand and wait in line/Do you think I got there being patient and kind?").
Freddy Krueger had (oddly enough, the rap numbers) "Are You Ready For Freddy?" and "Nightmare on My Street" made to coincide with the release of one of his films.
In Popeye, Bluto sings "I'm Mean" as he tears apart the Oyl household after Olive stands him up.
Although he's not a central villain, Nick Duran from Street Trash has a hilarious closing credits song available here. There's not really any spoilers to speak of, since this "plot" has little, if anything, to do with the rest of the movie.
In Eurotrip€, the main character's girlfriend is cheating on him with a member of a rock band, and said member writes a song about how he's screwing her while the protagonist is totally oblivious to it. Then he performs the song right in front of him!
Tommy has several, given that the entire thing is sung-through. The main villain, Tommy's wicked stepfather Frank, gets "Bernie's Holiday Camp," which introduces him and his sleazy attempts to mack on Tommy's mother, and a part of the song "Welcome," is about his plan to make Tommy's holiday camp overpriced. She eventually turns out okay, though. As far as supporting villains go, there's "The Acid Queen" for, well, theAcid Queen. For CousinKevin, there's "Cousin Kevin." WickedUncle Ernie gets "Fiddle About," where he "sings" about molesting the protagonist while he can't see or hear him. Towards the end of the film, Ernie also gets "Tommy's Holiday Camp," where he overprices the fees to get into Tommy's holiday camp and the related Tommy merchandise to rip off Tommy's followers. "Pinball Wizard" is a subversion; it certainly seems like it should be one of these, given that it's arguably the most memorable number in the film and it's sung by the arrogant pinball guy opposing the protagonist, but the song is actually about the opponent being impressed by the protagonist.
The Muppets has "Let's Talk About Me," which really has to be seen to be believed.
In Chicago, "All that Jazz", "The Cell Block Tango", "When you're good to Mama" and "All I care about" for Velma Kelly, the murderesses of Cook County Jail, Matron Mama Morton and Billy Flynn respectively.
Actually, every song in the production is a villain song with the lonely exception of "Mr. Cellophane".
The Russian film adaotation of The Shadow contains the song "To each his own language" sung by the Living Shadow. In the song, The Shadow explains how wonderful it is to fool and intimidate everyone.
Shadow: Just lend me your ear,
And if it's not deaf, I already know what to put in it!
The Russian film Masha and Vitja agains the Wild Guitars, contains the villains' introductory song "We are the Wild Guitars". Notably for being about the only time "hard rock" songs were allowed on Soviet TV (at least in mainstream production).
Another Russian film, "Secret of the Snow Queen", contains the song I don't Care, which is about how a person shouldn't care about anything but herself. Subverted later when we find that, while those manipulated by the Queen indeed don't care, The Queen herself actually does care - she is just deeply in denial about it.
the Russian adaptation of Peter Pan contains, of course, Hook's song. Among other, he comments that he hates all children.
There's actually one of these in Inherit the Wind, sung by the fundamentalisttownspeople who have organized into a lynch mob, and it's set to, of all things, The Battle Hymn of the Republic. "We'll hang Henry Drummond from the sour apple tree!" indeed. Fortunately, nobody actually gets lynched.
Phantom of the Paradise has several, depending on your perspective of who the real villain(s) is (or are). If one assumes that the murderous titular character is the villain, then there's his first song, "Faust", about selling one's soul for love, and "Phantom's Theme". If one considers the antagonist Swan to be the real villain, there's "The Hell of It", which plays over the credits. There's also "Life at Last", sung by drama queen Beef.
The villain Barnaby in the Francoeur version of Babes in Toyland gets "We Won't Be Happy 'Til We Get It" along with his henchmen in which he's cheerfully villainous, admitted he has no real excuse for it.