One planned episode for season 2 of The Adventures of Brisco County, Jr. (which got cancelled after the first season) had Brisco becoming the sheriff of a town.
Constantine: The fourteenth episode "Final Girls" would have introduced the character Judith, had the show not been canceled. Writer Daniel Cerone released the script online.
Coppers End: The original versions of episodes three, four, and five (the last of which is entitled "The Long Branch Saloon") were never filmed.
There were more episodes of The Culture Vultures planned after the five episodes aired that were never produced due to Leslie Phillips' health issues.
Emergency! had several. "Richter Six" got axed due to a writer's strike, but Chet breaking his shoulder during a rescue seems to have been used in another ep. "The Long Weekend" and "High Rise" are more. "High Rise" has a similar plot to "The Steel Inferno" movie but whether it was changed into the movie cannot be proven for sure.
During the Firefly reunion, various concepts for potential episodes were brought up:
Tim Minear elaborated on the vial and syringe Inara was seen with in the pilot episode "Serenity", explaining that it was a drug which, if she were raped, would cause the rapist to die a horrible death. Inara would have been kidnapped by Reavers, and the crew would track her down. When Mal enters the Reaver ship, he finds all the Reavers dead. He would then see Inara after she has been horribly brutalized, take her hand and treat her like a lady. According to Minear, this was one of Joss Whedon's first ideas regarding the kinds of stories they would tell through the series.
Alan Tudyk, Gina Torres and Sean Maher imagined the couples of the show (Wash/Zoe and Simon/Kaylee) having children and living onboard Serenity, with Zoe arguing with Jayne over who's going to teach the kids about guns.
Alan Tudyk also had a concept where they would transport feral dogs for dogfighting, and then River would commune with the dogs and actually tame them, rendering them useless.
Adam Baldwin came up with a scenario where Jayne would get his own ship and try to compete with Mal, fail badly and end up returning to Serenity a bit more humbled.
Nathan Fillion pitched an elaborate story with a moral dilemma that he heard from Whedon, where the crew would land on a planet and would be treated very well, before learning that the planet was dying and the inhabitants want Mal to help them escape. However the planet is so distant that if they take on refugees they will run out of air, unless they meet another ship. Mal pretends to agree, and while the crew are sleeping, takes control of Serenity and flees the planet. As they escape, they never meet another ship, and realize if they saved the people they all would have died. Mal then assumes responsibility for their actions, emphasizing that what happened was his fault alone.
According to a 2013 interview with Whedon “I had planned to do an episode of Firefly with Amy and Alexis and James Marsters as part of a travelling Shakespeare troupe. Because it’s sort of a staple of the John Ford Westerns, there’s always that over-the-top theatre guy. And I thought it would be terrific to have them to try and put on a play in the cargo bay.”
A fourth season of Gilligan's Island was planned, but cancelled at the last minute. Story treatments of the Season 4 episodes are available, though a TV retrospective suggested that actual scripts had already been written.
According to her memoir, Lena Dunham once pitched an episode of Girls, based on an incident from her own life, in which Hannah has a sexual encounter that might be construed as rape. The other writers shot it down, believing that rape just isn't funny.
Both Werner Klemperer and Richard Dawson have hinted that a seventh season of the series, which would have included a proper finale in which the war ends and the prisoners of Stalag 13 were liberated, was in the works at the time The Rural Purge happened, thus axing the series for good after its sixth season.
In The '70s, Larry Hovis began work on an After Show that would have focused on the original Heroes' children fighting in Vietnam; plans for the series were abruptly halted when Bob Crane was murdered.
It's Always Sunny in Philadelphia: The Whole Episode Flashback from Season 7's "How Mac Got Fat" was actually shot for a Season 6 episode which would've been called "The Gang Gets Successful." It got as far as editing when the creators decided they weren't satisfied with it - and successfully convinced FX they would salvage the footage for a later episode.
M*A*S*H had a ton of them, although most were unsolicited "spec scripts" that were probably never actually considered for production.
"Hawkeye on the Double", the most infamous example, was originally written for the first season, in which Hawkeye is secretly seeing two different nurses at the same time, and when they both find out about each other, they both pretend to be pregnant to get back at him. The subject matter was considered too risqué for television at the time, so the episode was never produced; the original script is a special feature on the complete series DVD set.
"Father Hawkeye Knows Best" was also written for the first season, and dealt with Frank's wife visiting the 4077th with the Congressman of Indiana, so the gang try to cover up Frank's affair with Margaret by having Margaret pretend that it's Radar she's seeing, and Frank is simply her confidant. In the end, it turns out Louise is actually cheating on Frank as well with the Congressman.
"The Contract" was written for Season Seven, and dealt with Klinger saving Charles's life after he was nearly killed by mortar fire when collecting rare spices in the Korean countryside; afterwards, Charles wants to repay Klinger for saving his life, while Klinger wants it in writing. (The Klinger-saving-Charles premise was later used as a subplot in Season Nine's "Operation Friendship", albeit without the contract element.)
"A Toast to Mildred" was written for Season Nine and has the subplots of Hawkeye indulging in a lobster cookbook from home, Klinger making his own perfume to sell, and B.J. suspecting Potter is cheating on his wife with Margaret, even though they're both simply emotionally drained from Army life and had been leaning on each other's shoulders.
"Peace is Hell" was originally written for Season Ten, and deals with a rumor that Klinger started that a ceasefire is in effect, and the war will soon be over, which starts a chain reaction of craziness among camp; it's possible this episode wasn't produced because it's virtually recycled from Season One's "Ceasefire".
Reportedly, there are many other unproduced M*A*S*H scripts in existence as well; titles for these scripts have been released, but no other details are available. They include: "War's a Grind" (written for Season One), "The Fighting 4077th" (written for Season One), "Yankees 7 - North Korea 8" (written for Season Two), "Hawkeye Go Home" (written for Season Three), "A Matter of Time" (written for Season Three), "The Tub" (written for Season Three), "The Key", or "Hawkeye for the Defense" (written for Season Three), "Dear Everyone" (written for Season Three), and "Up the Flagpole" (written for Season Five). Interestingly, "A Matter of Time" was written by Allan Katz & Don Reo, who were later hired as producers for the show during Season Five, while "The Tub," was written by Elias Davis & David Pollack, who were added to the writing and production staff later in Season Nine.
According to a Monk episode guide, there was going to be an episode where the detective solves a murder while on a cruise. The cruise line company that owned the ship was okay with it until they started making numerous demands. The producers eventually decided it was more trouble than it was worth and scrapped the episode. The script didn't go to waste though; it was adapted into the 2014 novel "Mr. Monk Gets on Board".
Mythbusters features a small amount of episodes where myths were actively being tested, but had to be stopped for various reasons:
A voluntary example occurred when testing one myth involving a common household item being surprisingly explosive. What they discovered turned out to be so explosive and easy to make by accident that they voluntarily destroyed the relevant footage and agreed to never disclose what they had learned due to it being far too dangerous to spread to the public.
Monty Python's Flying Circus: A sketch John Cleese found in poor taste was written but not filmed. (There is actually some controversy amongst the Pythons themselves as to whether it was filmed or not, but certainly never broadcast.) It involved a wine connoisseur showing off his wine cellar to a visitor, and after each tasting he reveals that it's "wee wee".
There were going to be episodes of Quantum Leap where Sam leaps into an animated character and a dog.
"Bodysnatcher", which was to be the second episode of the first series, but the filming of the series was delayed several months by an electrician's strike. During the hiatus, the writers decided it was the weakest episode and replaced it with a new script which became the finale "Me^2". "Bodysnatcher" was eventually realised as a DVD extra with storyboard images and narration by Chris Barrie. "Bodysnatcher" notably introduces the subplot about Rimmer having hidden the hologram personality discs, which runs throughout the rest of the first series.
"Identity Within", which was to be a Cat episode in series 7. It was dropped because it was far too expensive and CGI-intensive to ever realise on the show's budget, and was replaced with the Bottle Episode "Duct Soup". The script would also eventually be produced as a DVD extra using storyboards and narration.
"Dad" was supposed to be the first episode of series 3, resolving the series 2 cliffhanger of Lister's pregnancy, but the writers couldn't get it to work without seeming sexist. Its plot summary was included as Unreadably Fast Text at the beginning of that series. The script was not completed, but the first third of it was realised in a similar fashion to "Bodysnatcher" and "Identity Within".
When Sam & Cat was abruptlycancelled, four episodes were left unfilmed, cutting its 40 episode order down to 36. Nothing is currently known about these scripts.
The Sarah Jane Adventures was cut short because of the untimely death of star Elisabeth Sladen. Planned episodes included a season finale titled "The Battle for Bannerman Road" that would have seen a return appearance of Jo Grant and the destruction of the main character's neighborhood, an episode where Sarah Jane's supercomputer becomes human, an episode that would have revealed Sky is technically the Trickster's "daughter", and an episode featuring the first reappearance of Ace since her departure in Doctor Who explaining through flashbacks how she and the Doctor parted ways and what she had been up to since.
Scrubs: Production of season seven was cut short by the 2007 Writer's Strike and the show subsequently making a Channel Hop from NBC to ABC. As a result of all this, production of an episode called "My Commitment" was interrupted partway through. The footage that had been shot was recycled into the season eight episode "My Nah Nah Nah".
Seinfeld: "The Gun" (also known as "The Bet") was written as something completely different — a half-serious half-funny episode in which Elaine buys a gun for self-protection and Jerry bets her that she'll never even use it, among other plotsnote The B-plot would have had Kramer claim to have joined the Mile-High Club with a flight attendant, with Jerry and George making another bet that the story is bogus and trying to track her down to prove it. The script made it to table reading, but the cast felt it was too dark and not very funny, so it was shelved and ultimately never made. The writers hacked together "The Phone Message" in two days to be filmed in its place, and all the supporting actors would appear in later episodes. Meanwhile, the episode's unfinished nature and darker tone made it a fodder for a Creepypasta in which the real reason it was shelved was the disturbing and supernatural phenomena happening to the actors and crew.
Star Trek: The Original Series was originally going to have an episode entitled "He Walked Among Us", which would have guest starred Milton Berle. In the episode, Berle would've played a sociologist pretending to be God in a primitive community, and it would've showcased Berle's dramatic acting range. However, Gene Roddenberry was enraged when he discovered that the script for the episode had been rewritten as a comedy, so he ordered for the episode to be scrapped.
A Star Trek: Voyager episode where the Doctor is forced to kill someone to protect a patient, bringing him into conflict with the Hippocratic Oath.
The entire planned fifth season of Star Trek: Enterprise, due to the cancellation. Season 5 was to show the beginnings of the Federation and the roots of the Earth-Romulan War, and much of the material would be used in the Star Trek: Enterprise Relaunch novel series.
Torchwood creators were in talks with ABBA to do a musical episode. The plan never got off the ground.
Due to Ultra Q ending early to make way for its more famous successor, several unused scripts from the show were recycled for Ultraman, notably "Oil SOS" and "The Terrifying Cosmic Rays". More interestingly, the series finale was envisioned as featuring an Ultraman prototype as an alien villain instead of a superhero.
Ultraman was intended to run for 52 episodes, but due to the stressfulness of the series' fast-paced production schedule, it only ended up running for 39 episodes. Nevertheless, the never-made 13 scripts are still known in Japan, which feature stories that were later recycled for Ultraseven or saw the return of previous monsters (including some from Ultra Q), or even introduced completely new monsters (in fact, concept art for several of them exist◊).
Ultraseven's intended 23rd episode was "300 Years' Revenge", which would have featured an alien name Talk (トーク Tōku) who vows revenge against humanity for killing his family and attempts to reconstruct a superweapon to do so, as well as transform into a hate-powereddemon kaiju to battle Ultraseven. It was ultimately cut due to Troubled Production and replaced with "Searching for Tomorrow".
Ultraman Nexus premature cancellation caused by major network screwing saw an entire story arc unfinished, and it would have featured Nagi becoming the next host of Ultraman Nexus, further revelations about Nexus, new Space Beasts, and a lengthier struggle against the Big Bad.
WKRP in Cincinnati was going to have a 5th season Story Arc where it's harder to stay a top rated radio station than to become one, but the show was cancelled after season 4.
. Nothing is known about what the producers had to cut down.
