A House Pseudonym is a pen name that can be used by any writer at a given publisher. House Pseudonyms have been used to disguise that a long series has become a Franchise Zombie by allowing other authors to use the creator's name. They have been used to make a collaborative work look like it came from a single author, using a name that belongs to neither of the actual writers. In the internet age, some websites use them as well. It may be a conscious decision, or it may be the byproduct of giving a standard moniker to posters who aren't signed into the site.
- Hajime Yatate is a collective pseudonym for the Sunrise staff.
- This article on The Other Wiki will tell you some of them.
- Carolyn Keene of the Nancy Drew novels.
- Franklin W. Dixon of The Hardy Boys novels.
- K. A. Applegate of Animorphs.
- There is a real K. A. Applegate, but she left the series about halfway through to work on other projects while a string of ghostwriters kept it alive, though she did come Back for the Finale.
- V. C. Andrews — enough that that "author" has been publishing long after Author Existence Failure.
- Victor Appleton of the Tom Swift books.
- Victor Appleton II of the Tom Swift, Jr. books.
- Maxwell Grant of the Shadow novels (usually Walter B. Gibson, but also Theodore Tinsley, Bruce Eliott and on one occasion Lester Dent).
- Kenneth Robeson of the Doc Savage novels (usually Lester Dent).
- Inverted with Harry Potter. Due to the great complexity of the series, several readers thought Harry Potter was the work of multiple authors; however, J.K. Rowling rebuked those claims by stating seriously it's just me much to the awe of this disbelieving side of the fanbase.
- Erin Hunter of Warrior Cats
- James Axler of the Deathlands series and its spinoff, Outlanders
- Dr. Haha Lung: Author of a large number of books on war, martial arts, and ninjutsu such as Mind Control: The Art of Psychological Warfare. Due to the similar content and writing style of the books, for a time, this was suspected to be a pseudonym of Ashida Kim but he has denied it and has stated that Haha Lung is a house name used by Citadel Press, a former publisher of his books with whom he had a falling out years ago. He has also pointed out that Lung is a Chinese word for "dragon" and combining with the name Haha suggests "laughing dragon" (as in "Ha Ha") so this pseudonym is probably intentionally meant to be a pun of sorts. Kim has been taking issue with Citadel on what he perceives as theft of intellectual property and denial of royalties on past books published with this firm. He notes that the material in most of Lung's books is identical to the material in the books he published with the same company.
- Jack Mckinney: Author of the Robotech novels. Actually consists of James Luceno and the late Brian Daley. After Daley's death, Luceno would write three additional Robotech novels using the pseudonym.
- People who sign up for free webhosting services are a (virtual) example of this trope.
- Amazingly, few webhosts seem to check if signups really are this - this webhosting management discussion site is one such example. But, due to a bizarre Finagle's Law and legalities, amazingly, it's legal.
- Which leads to sign-ups with placeholder numbers, like (Manchester phonecode here) 0161 000 0000.
- "Anonymous Coward" at Slashdot.
- "Anonymous" at 4chan.
- Anonymous, the well-known "hacking" group. The one with the question mark and suit logo.