Someone, usually a supporting main character but not always, has to be obscenely rich for the sake of the plot. How did they get that way, if they aren't portrayed as especially hard-working or clever? One solution is to have them be an heir to the fortune of an Inventor of the Mundane, who earns royalties from something they came up with that's really popular and makes a lot of money. Perhaps their mother's uncle-in-law invented hole punchers, or their great-grandfather invented spark plugs, or their grandmother wrote one of the most popular novels of all time. Or maybe their father invented Toaster Strudel. Whatever the case, they're set for life without having to work. On one hand, this trope can include forms of intellectual property such as books or songs, and not just practical inventions as is usually the case with Inventor of the Mundane. On the other hand it allows the characters' competence to be even less related to their wealth, since the Royalties Heir didn't even have to work their brain by coming up with the thing and enjoys the benefits merely by being related to its creator.
Not to be confused with the heir of royalty. Although it's worth noting that inheriting a noble title (usually) means inheriting a chunk of land that goes with it, and the monthly rent cheques from the people farming it for you. (Which may or may not be all that large...)
- Captive Hearts: Suzuka's inheritance includes patents to some medicines.
- The Toaster Strudel example mentioned in the description is from Mean Girls.
- In About a Boy, Hugh Grant's character is obscenely rich and layabout because his father wrote a ridiculously popular Christmas song.
- An early draft of The Big Lebowski explains that the only reason The Dude has any money is because he's related to Erno Rubik.
- Envy: Dmitrioff invented a spray to vaporize Dog poo. We don't know how much money he made out of the deal but Nick Vanderpark, who spent four thousand dollars to develop it, became obscenely wealthy.
- Uptown Girls : Molly lives on the royalties from her dad's music.
- In the Nancy Drew graphic novel "The Fake Heir", the millionaires central to the action made their fortune designing fax paper.
- Lily Rowan in the Nero Wolfe stories is rich because her father built the New York City sewer system.
- From Larry Niven's Known Space stories, professional thrillseeker Gregory "Elephant" Pelton is a billionaire because his grandmother invented the transfer booth.
- Subverted with the protagonist of the Kiki Strike novels: her great grandfather invented control-top panty hose, but her family can't spend it because it is locked away in a trust fund that can only be spent on education fees.
- In Good Omens, one of Anathema Device's ancestor invented... the device. (Which is a part of clocks.)
- Roxy from Dead Like Me invented leg warmers. Unfortunately, her jealous roommate killed her and stole the idea, so she never got a chance to get rich or to have kids to pass the wealth on to. The murderous roommate, on the other hand, is now living the high life.
- In White Collar, Special Agent David Siegel is the heir to the elevator button fortune. He got sick of his peers using their money to screw the rules and joined the FBI.
- On Royal Pains, Tucker Bryant's grandfather supposedly invented the blender.
- Night Court once had a wealthy girl who had to choose between two men, a well-to-do rich man's son and a more rough-around-the-edges guy. First, the girl chooses the rich man's son with her mother explaining he's worth twelve million dollars. The other guy then reveals he's worth fourteen million, shocking everyone. He explains it's because his father invented the beer hat. Roz exclaims "You mean those dorky things are worth fourteen million dollars?"
- In Frasier, Niles' first wife Maris is unbelievably wealthy and an impossible snob. When the couple divorces, she cuts him off without a cent — until cutthroat lawyer Donny Douglas finds out that her family's fortune comes not from timber, as she tells everyone, but from urinal cakes! On pain of letting that get out to all her snooty friends, she agrees to a reasonable settlement.
- Million Yen Women: Hitomi is the daughter of deceased famous author whose books are still selling. She's apaprently making enough to be able to live comfortably without working.
- In the Dragon Age universe, the noble houses in Orzammar derive their nobility from being descended from Paragons. In theory, these Paragons represent virtues that dwarves revere. In practice, though, a lot of Paragons were basically inventors who just happened to invent something useful, making their descendants a bunch of royalties heirs with extra attitude... at least, according to Varric in Dragon Age II.
"And every person there thinks he's better than you because his great-great-great grandfather made a water-clock or something."
- In Danny Phantom, Sam's grandfather invented the machine that twirls cellophane around deli toothpicks.
- In The Looney Tunes Show, Bugs gets all his money from having invented the carrot peeler.
- Phineas and Ferb: Heinz Doofenshmirtz invented a device that corrects people's eyesight and the royalty checks he receives for this make him feel less uncomfortable about one of his inventions being used to do good.
- Jonny Quest: The Real Adventures: The Duntchecks from "The Haunted Sonata", thanks to a sonata authored by Franz Duntcheck. Once it was revealed the sonata was actually stolen from a woman named Anna Kafka, the wealth went to her surviving family.
- Dude, That's My Ghost!: When Mr. Minotaur becomes the Principal of Beverly Beverly High School and Alpha Bitch Lolo Calorie tries to use her father's wealth to intimidate him, he says he doesn't need bribes because one of his ancestors invented the receipt.
- Former Monkee Michael Nesmith's mother invented Liquid Paper, making him very, very wealthy.
- Taken advantage of by Lorraine Williams, the former CEO of TSR, inc., the company that published Dungeons & Dragons. As one of the company's side projects, she devoted massive time and resources towards creating and promoting Buck Rogers XXVC, including sourcebooks and computer games, despite the fact that the market for such a game was just on the plus side of nil. Naturally, the owners of the Buck Rogers trademarks would receive royalties for each such supplement sold. However, it just so happened that Williams herself was the heiress to those properties, which is just about as conflict-y as conflicts of interests get.