12 Monkeys: Seemingly averted by the premise of the series that history is mutable (as demonstrated when Cole scratches Railly's watch, causing a scratch to instantaneously appear on the future version of the watch). Nonetheless, the trope is played with:
Cole only travels back in time to meet Cassandra Railly because she leaves a message, recovered in the future, in which she mentions him.
In "Mentally Divergent", Cole is searching for the records of a certain patient in the the remains of a mental institution in 2043. Since the records are missing, he is sent back to 2015 to infiltrate the institution and find out about the patient himself. Cassandra visits the institution when she finds out Cole is there and in the process, steals the records of the patient in question, thus causing them to go missing in the future in the first place.
Cole first learns about the Army of the Twelve Monkeys from Leland Goines in 2015, who in turn only heard about them because a future version of Cole asked him about it in 1987.
The end of Season 2 reveals that the entire series up to this point has been one. It seems that the Witness engineered everything — the plague, the attempts to undo it with time travel, the Messengers' attempts to cause a Time Crash, and the attempts to prevent that — all in order to ensure that Cole and Railly, his parents as it turns out, would be in the right time and place to conceive him. Season 3 expands on this, as it turns out that the Witness was raised by the Army of the Twelve Monkeys and guided via time travel in gathering the people who would found the Army in the first place.
The Messengers themselves are an example. Super Soldiers created by the Army of the 12 Monkeys to travel back in time and kill the Primaries, one of them survives the mission and goes on to serve as the proof of concept for an Evilutionary Biologist working for the Witness, whose work would later be used to create the Messengers in the first place. Not only that, but that surviving Messenger would also end up (through cloning and normal birth, respectfully) being the mother of Olivia and the Pallid Man.
Olivia herself ends up being part of one as well. When she betrays the Twelve Monkeys in Season 3, she spends the whole season running a Batman Gambit to kill the Witness as revenge for how her whole life was manipulated for the Witness' plans, only for the season finale to reveal that Olivia herself, not Cole and Railly's son, was the true Witness, meaning that in the end she's stuck having to manipulate her own past self in the ways she hated in order to maintain causality.
Cole also turns out to be the result of a loop, as his mother turns out to be Hannah Jones, whose life he saves as a child, allowing her to grow up, become a time traveler, and go back in time to conceive him. Furthermore, it's his DNA which allowed for time travel to be survivable, enabling the creation of the 12 Monkeys and the virus, which Team Splinter created time travel to prevent.
Even the virus itself is part of a loop. It was created from the genetic material of an ancient corpse called "the Precursor", which in the Grand Finale is revealed to be the remains of Olivia herself, who was earlier stated to have a dormant version of the virus in their blood, and who is killed when a Splinter beam sends half their body back in time.
The Adventures of Brisco County, Jr. has the titular character go back in time to meet himself and take a necessary MacGuffin out of his own hands. Which is exactly what happened a few episodes ago.
The fifth season of Agents of S.H.I.E.L.D. heavily revolves around one of these. The team is sent into a Bad Future, where Daisy is apparently responsible for an Earth-Shattering Kaboom, and the remnants of humanity are enslaved by the Kree. After some investigation, they find out that they were sent there because Robin, a young precognitive, had a vision that they would be there. Fitz, who wasn't in that vision, was left behind, but he figured out a way to get to the future anyway. Elena also runs into her future self, who is tortured by the Kree to find out what the team is doing at that very moment, since she lived through it. Even after they return to the past, evidence keeps popping up, such as Simmons unwittingly keeping a White Monolith shard that her future grandson Deke would eventually use to help send the team back in time. In addition, several members of the team, having found out when they die in the loop, succumb to You Can't Fight Fate and start being reckless, believing that they can't be killed until then, despite still trying to break the loop. It is implied the weak point of the timeloop is when Elena meets her future self: since she already knows what her previous future self said previously didn't work, she can try to guide the present Elena to a solution by saying something different. It seems to work in the timeloop we see: let Coulson die.
The Andromeda Strain: The Andromeda contagion is actually revealed to have been sent from the future via Time Travel using a warp hole to send a satellite containing it, since in the future the only known cure for it was destroyed via deep ocean mining. The final shot of the series is of a disease sample being stored aboard a space station, suggesting that it will survive to reinfect humanity in the future while also implying that deep ocean mining will continue.
Babylon 5 has two of these, related to the same incident. The two-part episode "War Without End" in the third season has the protagonists cause the mysterious time incident on Babylon 4 that happened in the first season episode "Babylon Squared"... at the conclusion of which, an important character travels back even farther in time to become the cause of one of the show's central prophecies. During the last battle of the Earth-Minbari War Sinclair was abducted by the Minbari and his DNA indicated he was the reincarnation of their prophet Valen, prompting an immediate end to the war. But then Sinclair went back in time a millennium to become Valen.
Castle surprisingly features an example. While there is at least theoretically a non-time travel explanation for the killer's actions, it makes much less sense than this one. At the end of the episode, Beckett spills her coffee on a letter that was a piece of evidence in the case, which perfectly matches the picture of the letter that the killer was using. The killer's actions also make more sense if he is creating a time loop, as he is otherwise operating according to a shared delusion by taking actions in the wrong order.
In Children of the Stones the village of Milbury seems to be caught in a loop where similar characters go through the same set of events again and again. At the end of the series, as Professor Brake and Matthew leave the village, Joshua Litton arrives. Litton is identical to Rafael Hendrick, who had been brainwashing the villagers. The implication is that the story is about to start again.
Stephen Colbert (circa 2009-2509 or so), the main character in The Colbert Report, failed to stop Stephen Colbert (circa 2005-2009) from electrocuting himself, then took his place as host in order to be hosting the show in 2500 to come back in time so he would exist in his present to come back in time...etc.
Lesser known TV series Crime Traveller had this where two police officers travelled back in time to work out who committed a crime. Often when this happened they had already lived the experience and then travelled back in time to relive it. In the original version of time certain things happened that were strange/funny/helpful etc and it was only when they travelled back in time that they realised it was their future selves that caused these incidents to happen.
Dirk Gently's Holistic Detective Agency involves one of these. The central figure in the mystery that Dirk is trying to solve is a time traveler exploiting a stable time loop. Dirk and Todd travels back in time to meet Dirk's former self and give several clues that he'll need to get to his current position. This explains Dirk's casual confidence and occasional, inexplicable insights while seeming to not really know what's going on. Dirk also introduces Todd as his best friend, causing Dirk to seek Todd out in the first place.
Doom Patrol (2019): The concept of past events happening because of people affected by them inadvertently setting them in motion after traveling through time is explored in the third and fourth seasons, with the former having an arc where Rita Farr used Madame Rouge's time machine to go back to the year 1917 and inspired the Brain and Monsieur Mallah to invent the time machine they'd eventually hire Madame Rouge to use, while the latter would reveal that Isabel Feathers, the actress Madame Rouge knocked down a pit back in the second season, was actually this continuity's version of General Immortus and that she became an ageless, powerful being from spending eons trapped in the void of time, in addition to her essence being used by Niles Caulder to provide the Doom Patrol with their longevity, plus "Portal Patrol" revealing that Cliff Steele caused Caulder to become a paraplegic and inspired him to eventually go through with creating the Robotman body Cliff's brain would eventually be put into when Cliff confronted Caulder after time-traveling to the 1940s.
In an episode of Earth: Final Conflict, an archaeologist discovers a modified ID portal and a man's fossil from prehistoric times. The problem? The skeleton is that of a modern man who didn't exist at the time carbon dating established. Long story short, a medieval monk ends up traveling with Renee, chasing down a female Atavus who uses the modified ID portal to jump through time. The Atavus ends up killing him in prehistoric times, when the Atavus ruled the Earth, and cavemen were their food. Renee kills the female Atavus and impresses Howlyn before jumping back into her own time. Thus, the skeleton is that of the monk. Furthermore, the archaeologist speculates that seeing Renee in action likely caused Howlyn to try to make more humans like her using the DNA of the dead monk. If that is true, then it was their time travel into the past that ensured the existence of modern humanity.
The pilot of Eureka has Jack and Zoe drive into the titular town on a rainy night past a car... with them leaving. This is the first clue that this town isn't normal, and the argument over what they saw directly leads to the accident that leaves them temporarily stranded in Eureka. The series finale ends with Jack driving Zoe back to college... and passing their original selves driving in. Given the show's cancellation, we're not likely to find out which of the experiments caused this.
Zig-zagged in Farscape, in the first season, the Evil Sorcerer Maldis reads Crichton's mind and, as proof, tells him that he lost his virginity to a girl named Karen Shaw in the back of an SUV. In a much later episode, the crew ends up in 1986 trying to keep Crichton's father from going up on the Challenger on its doomed flight. Meanwhile, Chiana meets Crichton's younger self and whose name young John misinterprets as "Karen" and her "Ow!" (from touching hot metal) as "Shaw" (her blue skin is explained as part of a Halloween costume). The rest is history. So, yes, John Crichton boldly came long before he even knew aliens existed.
The Flash (2014) reveals near the end of Season 3 that Savitar is at the center of one of these: in an attempt to defeat Savitar, Future Barry created a series of time remnants, all but one of which were killed. That last one was rejected by Barry and the others, which caused it to eventually go insane from emotional pain. Deciding that the only way to avoid this was to become a god, the remnant went back in time, becoming Savitar in the first place.
Fraggle Rock: Mokey, researching an ancient leader named Blundig who caused some boulders to be moved, accidentally goes back in time, pretends to be Blundig, and causes the boulders to be moved. In the process, she also makes Fraggle culture closer to what it is in the present.
The "Boom Boom Machine" originated from one. Supposedly built by the First People, the machine was actually built in the future by future versions of the main characters and sent back in time millions of years to be discovered by the present-versions of the characters, who believed it to be an ancient device created by a mysterious race known as the First People, who were humans that evolved long before the dinosaurs. The present-day characters searched for all the pieces of the machine and reassembled it in order to try and fix the damage to space-time that interdimensional travel had caused. However, when activated, the machine creates a bridge between the two universes, forcing Fringe Team and alternate-Fringe Team to work together to repair the damage. Somewhat amusingly, future-Walter realizes that he has no choice but to send the pieces of the machine back through time in order to complete the loop, and calls attention to the fact that this represents a paradox.
Then there's the Series Finale, dealing with the Fringe team's attempts to repel the Observers-turned-Invaders. Walter accomplishes this by going forward in time to prevent a scientist from creating the Observers, so that they never travel back in time to meddle with us. Of course for this he needs the help of September, a humanized Observer now known as Donald, as well as the "defective" Observer child Michael, neither of whom should strictly speaking exist any longer.
A fantasy variation in Game of Thrones. Bran Stark uses his ability to see the past (and loosely interact with it) and ends up watching young Hodor (then known as Willis) acting normally. Wylis was a normal kid and not the mentally disabled Hodor, who repeats his name over and over. When the White Walkers attack, thanks to him going into Dream Land alone and accidentally alerting them, he ends up warging into Willis/Hodor's mind in both time periods. After Meera and him escape the Children of the Forest's cave where they were staying, we learn that Bran's Mind Rape of Wylis not only caused him to sacrifice his life holding the door to give them a chance to escape, but also damaged past Wylis' brain and the name "Hodor" itself is the past Willis hearing the present Meera's last words to him, "Hold the door", over and over.
In the Time Travel episode of Ghostwriter, the kids in 1928 solve their case by sending Ghostwriter to 1993 to find out how the case was solved, then bring the info back and use it to solve the case. As the kids in 1993 are reading old 1928 newspapers about the case, the pages start to turn blank — if they don't send the info back, the case will never be solved and thus the newspaper will never have it. Exaggerated by The Reveal of why solving this case is so important: One of the kids in 1928 grew up to be the surgeon who treated a condition that would otherwise have killed Jamal's father before Jamal was ever born. If this case didn't get solved, that kid would have been arrested for the crime and would never have been in a position to become a doctor. In other words, because Jamal and the Ghostwriter team helped solve the case, Jamal, and by extension, the rest of the Ghostwriter team, was able to exist to help solve the case.
In the Haven episode "Sarah", Duke Crocker finds a gold doubloon among his late father Simon's belongings. When he is sent to 1955, he meets a bartender who turns out to be his grandfather Roy. Duke pays using the gold doubloon, and Roy gives it to eight-year-old Simon as a birthday present. Later, when Nathan arrives in 1955 and is looking for Sarah, he runs into a little kid who asks if he could be a cop like Nathan. The kid turns out to be Nathan's father Garland, which means that Nathan inspired his father to be a cop, who in turn inspired Nathan to be a cop.
In the Hercules: The Legendary Journeys episode "Once Upon A Future King", King Arthur becomes a cruel and arrogant tyrant, so Merlin sends him back to Hercules' time. Hercules, Morrigan, and Merlin's past self (Merlin is very, very old) manage to redeem him, and in the process, the past Merlin learns that he will gain magical powers. When Arthur is returned to his own time in the end, Merlin reveals that he sent Arthur to the past because he remembered what had happened and knew Hercules and friends would able to redeem him.
Near-miss at the end of the second season of Heroes when Peter Petrelli almost becomes responsible for the end-of-the-world timeline he visited earlier, through his efforts to prevent it...but drops the Idiot Ball after holding tight all season, and destroys the virus.
HEX has an accidental Nice Job Fixing It, Villain one. Azazeal tries to psychologically torture Thelma by sending her back in time to the seventeenth century to be forced to watch Ella being tortured and nearly executed as a witch (which he brought about impersonating a witch-hunter). However, it turns out that Ella survived because Thelma interrupted her burning and frightened the villagers away.
Kamen Rider Kabuto received his belt from his future self, and later dealt with the Hyper Zecter being destroyed in the present by retrieving it from the future. Tendou at least seems to think this trope is in play as a result, although both the show and the movie offer contradicting evidence.
Kamen Rider × Kamen Rider Fourze & OOO: Movie War Mega Max consists of one for the OOO characters. By the end of the movie, Eiji is confident that he'll succeed in restoring Ankh's broken Core Medal someday because he's met a version of Ankh from the future, while Aqua has overcome his Cowardly Lion status through a Batman Gambit nearly forty years in the making.
Kamen Rider Gaim features multiple early appearances by a mysterious blonde woman resembling Mai, who delivers speeches filled with mostly vague-sounding gibberish about how accepting the Sengoku Driver will mean having to fight to the bitter end, "until the world is dyed in your image". The only one who seems to know who she is, DJ Sagara, calls her "Woman of the Beginning". She's eventually revealed to be Mai herself after gaining the power of the Golden Fruit near the end of the show and attempting to use it for time travel, something it is at least theoretically capable of. In practice, her messages to the past, in the ultimate example of That Came Out Wrong, were garbled and warped, becoming the cryptic appearances of the "Woman of the Beginning" that put them on that path. On top of that, Sagara knew just what to do in order to escalate the war because he took note of who the Woman of the Beginning appeared to - he knew who the major players were because he saw who the time-traveling owner of the Golden Fruit felt the need to approach, and helped push them down the paths they ended up taking.
Kamen Rider Zi-O reveals itself early on to be occuring in one, but the sheer magnitude of the loop isn't clear until near the very end of the show. The goal of the main characters is to stop Sougo from growing up into the tyrant Oma Zi-O and creating the Bad Future, but by the end of the first quarter it's clear that they're actually on the path to creating Oma Zi-O instead. What isn't clear is how, as Sougo is a kindhearted young man who forms strong friendships with the people who originally came back in time to kill him. As the show goes on, time gets more and more tangled into knots, with various characters being revealed to come from mutually contradictory timelines that only coexist because of the Time Crash that happens inside the loop. At the end of the show, the Big Bad establishes that he created the time loop in such a way that killing him would undo it, and in so doing would erase all of Sougo's friends from existence. There's only one timeline where all these possible realities coexist and Everyone Lives: the one where Sougo becomes Oma Zi-O, Swartz's Puppet King, and devastates the world so that everyone will go back to stop him. When Sougo does become Oma Zi-O, however, Swartz's plans get spectacularlydestroyed and it costs him his life, but nothing happens when he dies (especially since he killed two of his friends, Tsukuyomi and Geiz and his world got integrated into Sougo's, causing him to fade into nonexistance) and Sougo relinquishes his newfound powers to break this loop and undo the damage done.
Kirby Buckets: This is how Kirby's idol Mac McAllister got his nickname. His actual name was Rodney, and he played in a band with Kirby's mother in the '90s before having a bitter breakup. Kirby went back in time to change this, and when "Rodney" decided he wanted to change his name, Kirby called out "Mac?". And Mac McAllister was born.
During the "Invasion!" crossover episode of Legends of Tomorrow, the heroes send a team back to 1951 and a previous Dominator landing on Earth to capture and interrogate a Dominator and find out why they've come to Earth again in 2016. After an intervention by some Men in Black, Cisco insists that they free the Dominator (who is being tortured and will likely be killed) and send it on its way in a Dominator dropship Oliver, Digg, Sara, Ray, and Thea had earlier used to escape the Dominator mothership and was still on the Waverider, hopefully with the result that the Dominators will look kindly on the gesture. When they return to 2016, Cisco contacts the same Dominator and discovers to his horror that the reason the Dominators were landing on Earth and abducting people in 1951 was to check for the presence of metahumans, who the Dominators wanted to eliminate as a threat. Freeing the Dominator in 1951 provided proof there were metahumans on Earth (namely the team sent back to 1951), so they monitored the planet more closely and intervened in 2016 when they somehow detected Barry altering the timeline. This led them to attack Earth, have one of their dropships captured by some of the heroes in an escape, and that ship and the team with Cisco traveling back to 1951 on the Waverider to find out why the Dominators were invading.
There's another example which essentially Book Ends Season 1 of the show. In the pilot, Stein drugs a reluctant Jax in order to get him to come along on the team. In the penultimate episode of the season, Jax gets sent back via shuttle to the same day the team left in order to reverse some Rapid Aging brought on by an accident on the Waverider; to get back to the others, he recruits the pre-time traveling Stein to help him fix the shuttle, and before he leaves he forgives Stein for drugging him, which gives Stein the idea in the first place.
The Season 3 episode "Daddy Darhkest" reveals that one of these is responsible for Nora Darhk's Start of Darkness. An adult version of Nora was introduced earlier in the season as a member of the Cult of Mallus, a position which enabled her to resurrect her father Damien. In this episode, the Legends meet the younger Nora, who is suffering Demonic Possession from Mallus and fighting his corruptive influence... until her father shows up and reveals how joining Mallus willingly will give her the power to bring him back. She then voluntarily leaves with the Cult members, leading her to grow into the older version previously introduced.
Logan's Run: In "Man Out of Time", David Eakins created the Sanctuary Project in the hope of preserving humanity's knowledge as all signs indicate that a nuclear war is imminent. In December 2118, he uses his Time Machine to travel forward in time to 2319 in order to determine what caused the war. Eakins intends to return to his own time and use the information that he obtains to prevent it from ever happening. It turns out that the revelation that time travel was possible led to the outbreak of the war. Having realized that time travel could be used as a weapon, the United States' enemies, including the Eastern Bloc, launched a preemptive strike to ensure that it would never happen. The US responded in kind.
In the fifth season, John Locke may have just created one of his own: while time travelling to 1954, he tells Richard Alpert (immortal spokesman of the Others) his exact birthday, and encourages him to consider young John for a leadership role. Considering his current relationship with the Others, he may have pretty much written his own destiny.
An even bigger one occurs in "He's Our You" and "Whatever Happened, Happened": Ben torments and manipulates Sayid and others in the future. Sayid then travels back in time and shoots 12 year-old Ben, attempting to prevent Ben's later misdeeds. Kate, Sawyer, and Juliet, in order to save Ben, take him to the Others. This leads to Ben becoming the ruthless individual who later torments them, and who causes their time travel.
According to Daniel Faraday, this is how time travel in the Lost-verse works, except for Desmond for some damn reason.
In yet another loop in the fifth season, in "The Variable", Faraday himself is killed by his mother when he travels back in time to before he was born. His mother therefore knows, throughout Faraday's life, that she killed (the future) him, yet she accepts this "sacrifice" and uses every opportunity to strictly direct him along his destiny.
Also in the fifth season, Richard gives a compass to Locke, who then travels through time for a while and gives the compass to Richard in the 1950s. Where did the compass come from? Who manufactured it? Where did it go? Also shouldn't it age into dust? Perhaps it did age into dust, and Richard then created a new one which he gave to Locke and which became the same compass that had aged into dust.
Let's just say that Lost has confusing time travel. However, the clearest, unambiguous example in the show is "The Constant", in which Daniel's journal guides him to tell Desmond certain things to his past self, which his past self then records in the journal before losing his memory. Most notably, the frequency needed to make his time machine work came out of nowhere, since it was passed back and forth between Faraday and Desmond infinitely. Unless, that is, past Faraday already knew the frequency before Desmond showed up.
The plane crash itself. In the 1970s, The Incident occurred, which destabilised a pocket of electromagnetic radiation. The instability was kept in check by The Numbers being entered into the terminal in the Swan Station at regular intervals. Flight 815 crashed as a result of the numbers not being entered in time, thereby causing the release of some of the radiation. A few years later, some of the Losties travel back to the 70s, and, as members of the Dharma Initiative, hear about electromagnetic anomalies occurring at the excavation site for the Swan Station. In an attempt to neutralise the electromagnetism, thereby preventing the plane crash and all the associated trauma, they arrange to detonate the core of a Hydrogen Bomb next to the source of the electromagnetism. Of course, this causes The Incident, which destabilised the pocket of electromagnetic radiation...
Lovecraft Country: Atticus doesn't want to intervene in the past, for fear of messing up his future. However, it's then learned he already did, by saving his father (a teen then) from being killed by white racists. If he hadn't done so, he (probably, since Montrose might not be his birth father) wouldn't exist, and their trip wouldn't have occurred.
Lucifer (2016): In Season 6, Lucifer and Chloe's daughter Rory comes back in time to chew out Lucifer for disappearing before she was born and never returning. After spending most of the season investigating what few details Rory knows to try and figure out what happened, this culminates in Lucifer having an epiphany that rather that taking God's place as ruler of Heaven, his true purpose is to return to Hell and help the souls there find redemption instead of torturing them. Afterwards, they realize that this sequence of events wouldn't have happened if Rory hadn't grown up believing that Lucifer had abandoned her. Thus, before returning to her own time, she makes her parents promise to never tell her younger self what really happened, in order to preserve the loop.
A rather depressing loop appears in Misfits: In Season 2 the mysterious Superhoodie turns out to be Simon, who repeatedly helps the main characters and in the end dies Taking the Bullet for Alisha. However, in Season 3, Alisha gets killed, and Simon goes back into the past to save her, but as mentioned, ends up dying for her in Season 2, long before the death that he went back in time to prevent.
The Dawn French comedy anthology seriesMurder Most Horrid has an episode in which French plays an inventor working on a time machine. Her simple-minded husband's behaviour becomes so erratic that she bludgeons him to death with a wrench. After serving time for his manslaughter she returns home, completes the machine and travels back to try and stop herself, only to discover that the presence of herself from the future was what caused her husband to behave so annoyingly in the first place. She was even accidentally responsible for the wrench being in just the right place for her past self to pick it up...
In the first episode of season eight of Mystery Science Theater 3000, Mike and the bots discover that Earth has been conquered by apes over several centuries. They later learn that Mike Nelson's descendants began inter-species relationships with monkeys and apes, giving rise to ape-people and a gradual conquest. Then in the fourth episode, the Earth is destroyed by a nuclear bomb, but Professor Peanut survived due to the explosion sending him back in time. He wound up in Wisconsin in 2112 and married a Nelson woman, setting off the Nelson family ape fetish that would result in the ape conquest and planetary destruction.
One of Jim's Office pranks involves sending Dwight faxed warnings from "Future Dwight".
The Outer Limits (1995): In "Breaking Point", Andrew McLaren tests the chronological phase shifter, the CPS-1200, which his company Anderson Technologies has been working on without permission by travelling two days forward in time. He is so excited that he immediately runs home to tell his wife Susan. He is shocked to find her lying in a pool of her own blood, having just been shot. Andrew then sees a man fleeing the house and driving off in his car. He tries to stop him but is unsuccessful. As the car speeds away, the driver turns to look at Andrew and he sees that it is his future self. After returning to his own time, Andrew obsessively tries to prevent Susan's murder. However, the fact that he is becoming increasingly unstable due to Temporal Sickness means that all he manages to do is frighten Susan and put the final nail in the coffin of their already precarious marriage. Andrew becomes so frantic in his attempt to protect Susan that he accidentally shoots her.
In the premiere episode, Nick Cutter discovers a human camp (and human bones) in the Permian, as well as a camera with a picture proving his vanished wife had been there. In the first season finale, having been reunited with his wife, they travel back to the Permian where Helen convinces him to take her picture...which he suddenly realizes is the picture he'd discovered previously, and that the camp they just set up is the one he'd discovered originally. An actual change does happen to the past, however, which confuses things.
They also discover a human skeleton, but Nick determines that the skeleton is that of a man. The second time around, the same soldier who escorted him the first time goes with him and is attacked and mortally wounded by a Future Predator. Before dying, the soldier realizes that it was his skeleton they found.
There's also a Medieval knight who follows a dracorex through an Anomaly on a quest to rid his village of the "dragon" and discovers that he has arrived into Hell (actually, modern-day London). Later, he finds a monument dedicated to himself and is made to realize that the monument describes his life after coming back and "killing" the dragon. He's supposed to marry the local lord's daughter and have several children. He goes back, reports the dragon dead, and kisses the lord's daughter, something he wouldn't know to do without going to the future.
The series 3 finale centres around the 333 site, a site in Africa where the remains of 14 hominids were found, having died in mysterious circumstances. It's revealed they were poisoned by Helen Cutter to stop humanity evolving and destroying the world.
One episode of Quantum Leap involves Sam leaping into the body of the sidekick to the host of a children's science fiction show about time travel…who also happens to be a bit of a crackpot amateur scientist trying to invent a time machine. Sam's task is to stop him from being committed to a mental institution. Sam succeeds, and the next episode of his show sees the man get a fan letter from "Sammy B" asking how he invented time travel. The host then goes on to explain his actual theory of time travel...which, it turns out, is the same theory that Sam himself used to invent time travel and form Project Quantum Leap. Even better? Sam taught him that theory earlier in the episode.
"Ouroboros" reveals that Lister is his own father. He left his baby self three million years in the past so that the resulting time loop would stop the human race ever truly becoming extinct.
In "Future Echoes", Lister has a bizarre conversation with Rimmer, in which Rimmer's side of the conversation seems to be completely random. Unbeknown to Lister, he is witnessing Rimmer's half of a future conversation. Immediately after future Rimmer walks away, present Rimmer appears and they have a conversation about the vision Lister had. During this Rimmer says everything Lister just witnessed. This conversation would not have proceded this way and Rimmer wouldn't have said those things unless Lister had already seen him say them.
In "Give and Take", the crew visit a space station where a mad medibot apparently steals Lister's kidneys, which are destroyed in the resultant firefight. They learn the station was also home to a technician who discovered a way to intentionally create a stasis leak. (He was warned by his future self to stop doing so, or he'd go back in time and stab himself, and was so annoyed at hearing this that he stabbed himself. Wracked with guilt, he went back in time...) They use this to steal Lister's kidneys from the day before, realising that what he'd been feeling at the start of the episode wasn't a hangover, but the effects of the operation and the miniaturised dialysis machine. (And, presumably, the kidneys that were destroyed actually came from another victim.)
In one episode of The Red Green Show, one of Ranger Gord's educational shorts had him teaming up with his future self and going back in time to prevent a forest fire. After the two meet and team up with Past Gord, Future Gord explains his information shows the fire will be caused by lightning, which strike Red and Harold. The three Gords violently put out the fire and after looking like the usual "Everybody Laughs" Ending, the three Gords decide to go to the future and celebrate. However, sparks from the time machine taking off end up causing the fire in the first place.
"Crisis" involves Clark covering a shift for Lana at a teen crisis center, whereupon he receives a call from a terrified Lana. The call turns out to be from the future and the only reason that Lana ends up making it in the first place is because she hears the recording of the first call and knows that something bad is going to happen to her.
"Apocalypse", Clark goes back in time back to Krypton to protect his baby self from Brainiac.
Space: 1999 combines this with and Revision and Dénouement. In 1999, almost 25 years after the series ended, a short Fan Film called Message From Moonbase Alpha was produced and shown at a fan convention. Actress Zienia Merton explains that moonbase systems are failing, that the Alphans have found a planet they are going to take their chances living on, and implores the people of Earth to remember them. This is revealed to be the "Meta signal" that drove the plot of the first episode.
In the Stargate SG-1 episode "1969", the team travels back to the title year and has to figure out how to get home, meeting a young General (then Lieutenant) Hammond, two hippies, and a young Catherine Langford. General Hammond sends a note back with them that Captain Carter is not allowed to read until after they go through the gate. The note contains cryptic instructions as to how to get home, as well as instructions from General Hammond to his younger self to help the visitors (that from his POV writing the note he has already helped). It is later revealed that General Hammond has been waiting for years for the sign that it is time to send the note (evidenced by a large cut on Captain Carter's hand). When the SG-1 team manage to travel back to the future, they accidentally ended up jumping several decades in the future, far from their own time, arriving on a deserted SGC. There, they meet an old Cassandra (the human girl they rescued on a planet attacked by the Goa'uld in "Singularity"), who was expecting them in order to guide SG-1's return to their time, stating that sometime between their return and her meeting with them in the future, they told / will tell her to meet them there so they could return to their time.
Referenced but not used several times in the episode "Trials and Tribble-ations". The Temporal Investigations agents specifically loathe Stable Time Loops. Also, Bashir is hit upon by a woman who has the same name as his great-grandmother. After commenting on the fact that nobody knew his great-grandfather, he attempts to argue to O'Brien that he has to go sleep with her in order to ensure his own existence. O'Brien dismisses the notion, causing Bashir to declare that he can't wait to see the look on O'Brien's face when he finds out Bashir never existed.
The Prophets form a part of one. Sisko meets them in 2369, informing them that they are the gods of the Bajorans. That they sent the Bajorans "Orbs". Thing is, the Prophets live in a wormhole, and exist outside of time. From their wormhole, they can simultaneously access any era of history (Shown when they bring an ancient Bajoran to the present, then take him back to his time). So the Prophets, upon being told that this is what they do... do it. They send the orbs back in time, and begin acting as gods to the ancient Bajorans, causing the culture that Sisko gets to know... and then tells them about on his first meeting.
Sisko's own existence. Sisko is the Emissary of the Prophet, and discovered the wormhole. This caused the prophets to possess Sisko's mom, so she'd marry Sisko's dad, ensuring Sisko's birth. The only reason the Prophets did this, is because they met Sisko in the future (and being outside linear time, realized the role they played in his life, and thus took it upon themselves to make it happen).
In the second season of Star Trek: Discovery, the ship has been running around investigating mysterious stellar bursts created by an entity dubbed the Red Angel. They eventually figure out that it's actually a human wearing a time travel suit, but the occupant turns out to not know anything about the bursts. In the season finale, the crew creates a new Red Angel suit, which Micheal pilots in order to create the bursts that led the crew into their current situation in the first place.
This also plays into the rise of Season 2's Big Bad: while investigating one of the Red Angel's signals, the Discovery crew encounter a probe that came back in time from the Bad Future that the Red Angel is trying to prevent, infected with an AI that wiped out all sentient life. That AI then reaches out and infects Section 31's threat-assessment program, Control, causing it to begin developing consciousness and evolve into that murderous AI in the first place.
Referenced almost explicitly in the two-parter "Time's Arrow". Data's head is found in a cave on 24th century Earth, left there centuries ago by Data travelling into the past and losing his head, who got stuck in the past to start with while investigating where the cave head came from. Guinan was living in San Francisco in the 19th century at the time Data was sent back to, and it's through Data and the subsequent rescue mission in which she first met Picard. When the events begin to unfold in the future, Guinan goes to Picard and insists he accompany the away team, or else she and Picard will never meet, thus ensuring the timeloop is closed. It's put in as something of a Shout-Out to sci-fi fans: Samuel Clemens (aka Mark Twain) receives his own watch from the Enterprise who have time-travelled back to his period in history after recovering the watch from a cave in the future. The end of the two-parter concludes with Clemens in the same cave in that time period, looking at the same watch ... and, with a chuckle of amusement, putting the watch down again so the Enterprise crew will find it in the future, thereby sentencing the watch to an eternity inside one, as the watch was put there by Clemens to trigger off the loop to begin with.
In "Tapestry", it's shown that in his Academy days, Picard reacted to being stabbed through the chest by laughing heartily, with no apparent explanation. In the episode, Q sends him back in time to restore that timeline by allowing himself to be stabbed once again, and once again he laughs, this time apparently with happiness and relief that he has restored his own future, and with the ironic realization that this violent event was so critical to who he was. It's unclear if this is somehow a stable time loop caused by Q, or if the original reason for laughing was unrelated and was simply replaced by the new one.
Star Trek: The Original Series: In "Assignment: Earth" Gary Seven dictates a log entry stating that the mission was completed despite "the accidental interference with history by the Earth ship from the future". Kirk and Spock inform him that their historical records for the date describe a "never generally revealed" detonation of a nuclear platform at exactly the same altitude as the one Seven just destroyed after Kirk decided at the last minute to trust him, indicating that their actions were part of the timeline all along.
Star Trek: Picard: The season 2 finale has several. After first traveling to the 21st century, Picard notes that when the Picards returned to their chateau, they found bullet holes in the walls, assuming them to be caused by some criminals. The season finale shows a firefight at the chateau, and Picard notes the holes' location is an exact match to what he remembers. Also, Picard deliberately closes a loop by hiding the chateau's skeleton key behind a false brick, knowing that his teenage self is going to find it in the future and use it to unlock his mother's door, resulting in her committing suicide. Q commends him on avoiding the temptation to change his own past and accepting it instead. Finally, the Borg Queen that attacks Starfleet in the season opener is, in fact, Agnes Jurati, who has merged with the Queen to create a new collective, this one based on cooperation rather than assimilation. And the "attack" was an attempt to harmonize the shields of every ship in order to stop a Negative Space Wedgie from wiping out billions of lives. Although the only reason that timeline even exists is because Picard originally initiated self-destruct, resulting in Q transporting him and the others into an alternate timeline, which resulted in them performing a time warp to fix history.
In "Time and Again", Voyager witnesses the destruction of a civilization. When Janeway and Paris are accidentally sent back in time a few days before the incident, it turns out that the crew's attempt to rescue them is what triggers the disaster. Fortunately Janeway stops the attempt and the timeline returns to normal.
Features prominently in the three-part episode "Future's End". Captain Braxton, from the 29th century, goes back to the 24th century in a single-passenger timeship to destroy Voyager to prevent a 29th century disaster. Voyager fights back, causing the timeship's systems to malfunction and transport both ships to Earth in the late 20th century, with Voyager arriving later. The timeship itself crashed and was scavenged by an opportunistic businessman who used its technology to jump-start the Information Age, which allowed the 29th century technology to exist so it could be scavenged. Towards the end, the businessman tries to pilot the timeship to the 29th century, but his inexperience will result in the catastrophe that started all this. The Voyager crew prevents this, and everyone is safely returned to their proper place and time. So somehow, the middle of the loop is preserved despite no longer having a beginning.
Implied during the "Year of Hell" arc. The captain of the ship behind the constant fluctuations in the timeline created his ship to prevent an enemy from having conquered his. While he succeeded, a plague caused by their absence wiped out his family. He continued tinkering with the timeline in an attempt to restore his family. Ultimately the timeship was destroyed, reverting the timeline to its original course... where the captain is studying to build a timeship to keep his people from being conquered.
In the episode "In the Beginning," Dean's actions help to set many elements of the series in motion, from encouraging his father to purchase the Impala that Dean later drives, to accidentally focusing the attentions of the Yellow-Eyed Demon on his mother, Mary. The creator of the show noted that this concept confused Jensen Ackles a bit. He was told to just go with it. It was stated that what had happened was fate, and that Dean wouldn't have been able to change the outcome. He had been sent back just to witness the events. Which is weird, because an angel later goes back in time to try to change it all. She fails, of course, but it has nothing to do with fate.
In a cleverly done example by the writers, the season 9 episode "King of the Damned" had Big Bad Abaddon bring Crowley's only son to the future. And in the end, he stayed there Which one would at first think would screw up an earlier episode where Bobby used Crowley's dead only son to get himself out of his contract. However, when taking the events of subsequent seasons into account. Bobby was killed of for real in season 7 (in an unrelated event), long before Crowely would have claimed his soul. And it was revealed in season 8 that even if he was out of his contract, Crowley was going to take his soul to hell regardless On top of thatAbaddon kidnapped his son on the day he was going to die out in sea anyway via storm, so his disappearance didn't have any real effect on the world. So in the end, the past was manipulated with little to no affect on the present (and canon).
Terminator: The Sarah Connor Chronicles: Fischer only survived Judgement Day and taught the machines the things he did because he was in prison — thrown there due to his future self planting a backdoor into military computer systems, having logged in, of course, with his own retinal scan.
On a larger scale, the overarching plot is that SkyNet and Future John Connor are waging a temporal war in which SkyNet tries to create a Stable Time Loop that guarantees is own existence while John tries to break the loop, or failing that Trick Out Time so that SkyNet's future defeat can be guaranteed.
When visiting Chicago in 1992, Darien visits the restaurant that was famous in 2192 and orders his favorite dish there: an award-winning chicken pot pie. The pie is terrible. While tracking down the fugitive of the week, he has his AI Selma look up a 22nd century celebrity cookbook to find the chicken pot pie recipe the restaurant uses in his era. Then he gives a copy to the chef right before leaving town, thus enabling the place to start winning awards, become famous, and end up serving what would become Darien's favorite dish two hundred years later.
The show can't seem to decide if the events take place in the past or a time-shifted Alternate Universe. For example, in several episodes, Darien leaves messages for his boss in the future by having Selma put ads in certain newspapers. This would clearly indicate the first version of events. However, the second version is stated many times. In fact, Darien is usually unconcerned about how his actions might affect the timeline, indicating that he knows it won't affect his future.
This is discussed in an episode where one of the escape criminals is a huge fan of a late-20th century country singer, who will be huge in the future. Right now, she is just starting out. The criminal becomes her anonymous benefactor, sending her things like a guitar and boots, that he bought in his own time and actually belonged to her. After kidnapping her, he reveals that he has recordings of all her songs, to make her life and career easier. After defeating and sending the criminal back, Darien talks to her about her future career, explaining that, since this is an alternate reality, there's no guarantee that it will be as successful as in his own past. She then leaves before telling him of a new song she thought of about him. Darien is stunned to realize that his favorite song is about him.
An interesting one in an episode of The Time Tunnel. The time-traveling protagonists, Tony and Doug, are sent to Russia in 1956 to investigate a Soviet version of their 'Time Tunnel' project that was active at the time. The reason they are sent on this mission is because the head of that Soviet project, a scientist named Boraki, has defected to the West in the present (i.e. 1968) and offered to work on the US 'Time Tunnel' project; and Tony and Doug are supposed to investigate Boraki in the past by infiltrating his project. However, Tony and Doug's actions in 1956 result in the Soviet time-travel project being sabotaged, and this causes Past Boraki to swear revenge against the Americans...which he seeks to accomplish by infiltrating their Time Tunnel project twelve years later! Basically, Boraki wouldn't have approached the US in 1968 had Tony and Doug not sabotaged his project in 1956, and Tony and Doug wouldn't have been in a position to sabotage Boraki's project in 1956 had he not approached the US in 1968.
At the end of Timeless, Lucy time-travels from 2023 to 2014 to give Flynn her journal and start him on his journey of taking down Rittenhouse.
In "The Last Flight", the terrified World War I Flight Lieutenant William Terrance Decker abandons his friend and flying partner Alexander Mackaye, whose plane is surrounded by seven German ones, on March 5, 1917. He flies through a strange white cloud and travels forward in time to March 5, 1959. When he lands at Lafayette Airbase in Reims, France, Decker learns that Mackaye survived the dogfight and went on to save hundreds of lives during the Blitz. He then realizes that he must return to his own time and save Mackaye to ensure that the course of history is preserved. Decker does so at the cost of his own life.
In "A Hundred Yards over the Rim", Chris Horn's eight-year-old son Christian is dying of pneumonia in 1847. When he is sent forward in time to September 1961, Chris finds an encyclopedia which states that Dr. Christian Horn, Jr. was a pioneer in vaccine research for childhood diseases in California who died in 1914. After returning to his own time, Chris tells his wife Martha to give Christian a dose of penicillin that he obtained in 1961, which cures his pneumonia.
In "The 7th is Made Up of Phantoms", Sgt. William Connors, Private Michael McCluskey and Corporal Richard Langsford travel back in time to the Battle of Little Bighorn on June 25, 1876 and are killed by the Sioux. Captain Dennet and Lt. Woodard later find their names engraved on the Custer Battlefield National Memorial, though Woodard believes that it is merely a coincidence. Dennet regrets that they couldn't bring their tank back with them.
In "Act Break", Maury Winkler uses Harry's amulet to wish for a better writing partner instead of wishing for Harry to come back to life. He is transported to Elizabethan England and immediately meets William Shakespeare. Taking the amulet from Maury, Shakespeare wishes for Maury to work with him. Maury's mind is then filled with every line from all of Shakespeare's plays. It turns out that Shakespeare's greatest works were written by Maury using his knowledge of the future.
In "One Life, Furnished in Early Poverty", Gus Rosenthal is sent back in time to the 1940s and acts as a mentor and surrogate father to his younger self, who had a difficult relationship with his father Lou. Eventually, the older Gus realizes that he must return to his own time as his presence in the past is making him sick. When the younger Gus finds out that he is leaving, he angrily tells his future self that he will be a "big something" when he is older and will beat "Mr. Rosenthal" up if he ever sees him again. The older Gus then remembers meeting Mr. Rosenthal as a child and vowing to become successful because he was hurt at him leaving.
Implied in "Grace Note". Rosemarie Miletti enters her future self's dressing room on March 22, 1986 after being sent 20 years forward in time. The older Rosemarie and her sister Dorothy are unable to see her but it is implied that the former knows that the younger Rosemarie is there because she remembers her own experience of traveling through time 20 years earlier.
In "The Once and Future King", the Elvis Impersonator Gary Pitkin meets Elvis Presley on July 3, 1954, two days before he recorded his debut single "That's All Right". After he accidentally kills Elvis the next day, Gary usurps his identity and goes on to become the King of Rock & Roll. He later realizes that this was always meant to happen.
In "The Convict's Piano", the elderly convict Eddie O'Hara tells his fellow prisoner Ricky Frost that he was framed for murder in 1928 by the gangster Mickey Shaughnessy, who disappeared shortly afterwards. Ricky later discovers that playing a particular song on the old prison piano sends him back in time to the relevant era. When he plays "Someone to Watch Over Me", he arrives at a party being thrown by Shaughnessy in 1928. When Shaughnessy plays "S' Wonderful" on the piano, he is sent forward to 1986, which accounts for his unexplained disappearance in 1928.
In "The Junction", after becoming trapped in a cave-in on September 16, 1986, the miner John Parker realizes that he is not alone. He finds that another miner named Ray Dobson is trapped with him. After talking to Ray for a few minutes, John realizes that he has been sent back in time to September 16, 1912. While they are waiting to be rescued, John and Ray tell each other about their respective wives Melissa and Sarah. In 1986, Melissa receives a letter from Reverend Bailey that was supposed to have been delivered to her the previous day. After Ray is rescued, he discovers that John has disappeared, having returned to 1986. Ray writes a letter to Melissa and entrusts it to the church. His plan to alter history failed as John being sent back in time was always meant to happen. If it had never happened, Ray would have died. However, the letter contains John's location and the rescue team is able to find him in time.
In "Profile in Silver" JFK's replacement at his assassination by a distant descendant is indicated to be this by a coworker of the descendant with her specifically saying that altering history is impossible because even the act of time travel is part of history.
"Cradle of Darkness" involved a time traveler named Andrea Collins going back in time to kill Adolf Hitler as a baby. The episode ends with her jumping into a river with the infant. Both drown. However, the Hitlers' housekeeper immediately buys an infant from a homeless gypsy. Alois Hitler rechristens the baby Adolf and acts as though nothing has happened in order to spare his wife Klara the trauma of losing a fourth child. It's that baby that grows up to be the monster that Andrea was trying to stop.
"Memphis" involved Ray Ellison, who is dying of a brain tumor. He gets hit by a car and knocked out and somehow gets sent to around the time Martin Luther King Jr. was assassinated. He decides to try to prevent it, but he gets sidetracked helping a woman named Adelaide Tyler and her young son, Lucas. Ray helps Adelaide stop her house from being foreclosed and encourages Lucas to study, get a good education, and not ruin his schooling by getting into fights with bullies. He then saves Lucas from getting hit by a car, which makes him too late to save King. He wakes up back in the present and finds that he had received the surgery to remove the tumor while he was unconscious, even though he couldn't afford it. He then finds that the doctor who saved him is the grown up version of Lucas, who remembers him and quotes something Ray had told him as a child.
Kengo Manaka, the hero of Ultraman Trigger: New Generation Tiga gains the power to become the eponymous character when the ghost of Yuzare leads him to a statue on Mars, just as one of the Giants of Darkness that was defeated by Trigger 30 million years ago breaks out of their Sealed Evil in a Can status and frees the others to continue their campaign. Along the way, Kengo acquires the ability to Type Change via energy downloaded into his arsenal from a pair of stone ruins. Eventually, Kengo is sent back in time by Carmeara as part of some Wrong Context Magic, where he discovers that Trigger was one of the Giants of Darkness during their original attack. With the aid of a power boost from the then-still living Yuzare, Kengo is able to merge with Trigger and convince him to pull a Heel–Face Turn, causing him to transform first into Kengo, and then into all three of Trigger’s forms at once. During the ensuing battle with the Dark Giants, Trigger Power and Trigger Sky are dispersed into energy that gets sucked into a pair of buildings (which Akito confirms in the next episode became the two stone tablets), the Giants of Darkness are sealed away, Trigger Multi falls to Mars and turns into a statue, with his soul leaving his body and roaming the planet until 20 years before the main story, reincarnating as the present day Kengo. Oh, and Yuzare ends up dying from the strain of helping achieve all this, becoming the ghost version seen in the present.
A key aspect of Watchmen (2019) ultimately turned out to be caused by this: the murder of Police Chief Judd Crawford, who turned out to be a member of the Politically Incorrect Villain group the Seventh Kalvary/Cyclops and had a Klan robe. After awakening Dr. Manhattan and knowing how his view of time works, Angela Abar asks him to have his past self ask her grandfather and Judd's killer, Will Reeves, how he knew these things. As it turns out, asking Will is what informed Will about Judd's connections, setting into motion the events that'd lead to Judd's death.
Winnie the Pooh: The Book of Pooh has a story that's somewhat close to this trope. The story "Once Upon a Happy Ending" opens with Tigger hanging upside down in a tree with honey jars stuck to his paws. He wonders what's going on and the Narrator explains that he accidentally opened the book to the end of the story. He suggests they go back to the beginning so they can find out what happened and Tigger agrees. It turns out that in the story, Tigger is trying to help Piglet to retrieve an acorn that he lost. Along the way, he gets a couple of honey jars stuck on his paws. Eventually, he learns that retrieving Piglet's acorn would require him to climb a tree, but at this point, he says "no way" because he's already seen what happened. He backs away from the tree, but trips and ends up getting catapulted into the tree.
