Visions of Another Self

A scene or series of scenes that takes place in the past or future, real or imagined, using the same actors as the existing show but as different characters. To properly count for this trope, the relationships of the characters in the vision must reflect on the relationships of the existing characters, often with a plot-relevant Aesop for the characters to learn from it.

Occasionally Visions of Another Self occur by having a character actually travel to a place, whether it's in the actual past, an Alternate Universe or a Mirror Universe. Just as, if not more often though, it will be a constructed fantasy, a dream, a hallucination, a flashback (or someone else's flashback), a holodeck experience or the fantasy equivalent thereof, part of a Vision Quest or just a very active imagination. The probability of one of these occurring increases dramatically if Reincarnation is involved. Other times, this is done without the present-day characters even being aware of the past, but the writers playing up the parallels between the two for the audience's benefit.

Sort-of-but-not-really related to Flash Back. Superficially resembles an ad hoc Commedia dell'Arte Troupe. If the character having these dreams starts to think that they are the true reality and the rest of the show is the dream, it's a Cuckoo Nest. See also But You Were There and You and You.

Anime & Manga

 * Ancient Egypt in Yu-Gi-Oh!!; the characters there are said to be reincarnations or parallels to modern-day characters, which is another plot point in itself.
 * The final episode of Neon Genesis Evangelion has a short section in which Shinji dreams about how his life could have been if the show he was in wasn't a Deconstruction. It almost reaches Uncanny Valley levels.

Comic books

 * Used again and again in Donald Duck and Mickey Mouse comics to provide "fresh" story ideas, because of their overall premise being basically "invent stories about these popular characters" and little else. Sometimes handwaved by invoking Identical Grandson, but more often the whole story just is like this without explanation.
 * Several DC Comics Elseworlds play with the idea of the DC heroes and villains existing in a different era: Batman as a privateer, Old Western Justice League of America, Steel in times of slavery, Superman in the Middle Ages, etc.

Fan Fiction

 * At one point in Sailor Moon Z, the main Senshi do a body-switch with their Silver Millenium counterparts. After they're returned to the present, they have more frequent Flashbacks of their past lives, usualy overlaping with similar moments in the present.
 * The original also has flashbacks to this time though only when key to the plot.
 * In Stars Above, Oriko has these.
 * In the Azula Trilogy, at one point during Azula's trip to the Spirit World, she's shown visions of herself in other worlds, including one where she was banished instead of Zuko, and one where she was apparently born a peasant.

Film

 * Teenage Mutant Ninja Turtles III did this somewhat ridiculously and for no good reason by having an ancestor of Casey Jones (and played by the same actor) be a British ne'er-do-well stuck in Ancient Japan for some reason (presumably so that April O'Neil would have someone to relate to).
 * In the movie of Buffy the Vampire Slayer Buffy has dreams of her and her watcher as previous slayers and watchers.

Literature

 * In Teresa Edgerton's The Grail and the Ring, travel between the 'real' world, Ynys Celydonn, and the Alternate Universe of the Inner Celydonn, is introduced. One of the first rules of such travel is to avoid meeting yourself if possible, because to do so courts madness.
 * Dame Ceinwen, despite being the most powerful witch in Ynys Celydonn, is largely restricted to the role of The Watcher in this book - partly because she is so powerful, but also because she has already been in the times and places of the Inner Celydonn that are critical to the current problem, and cannot risk being there twice.
 * Prince Tryffin is sent to Fairyland, which is an Alternate Universe version of his own father's castle - the version of his homeland featured in travellers' tales, in fact. When he meets his own counterpart he finds the experience very disturbing, and quickly takes a dislike to the man. He comes to the conclusion that this is largely due to being unsettled by seeing himself from the outside.
 * The Big Bad of the story is the Inner Celydonn version of an historical figure who went mad from experiencing this.
 * The third book in Legends of Laconia has this as its main story. Reincarnation is involved.

Live Action TV

 * Happens practically Once an Episode on Scrubs; JD's daydreams put his coworkers into a number of absurd situations (and costumes.) This includes characters from Grease, West Side Story, and Star Wars, as well as occasional scenes that Parody a traditional Dom Com.
 * Charmed has shown the Halliwell Sisters' past lives on several occasions. These previous incarnations of the Charmed Sisters have always looked the same as the present-day incarnations.
 * When this was first done, it was explained that the previous incarnations looked different but the Halliwells "recognized" their spirits and thus saw them as their current selves. Later episodes sometimes overlooked this.
 * Mighty Morphin Power Rangers featured an episode where Kimberly traveled back in time to the Wild West, where all of the inhabitants resemble citizens of present-day Angel Grove, including people who look like the Power Rangers (except for Kimberly's ancestor, who makes a brief cameo after the present-day Kimberly returned to her time), Bulk and Skull (who try to find out the identity of the Rangers), and even The White Stranger. (Three guesses who that is suppose to resemble. Hint: It's the White Ranger.)
 * Kamen Rider Hibiki takes place around 2005. The Movie takes place in the "samurai era" but features parallel versions of all the main characters. A few of them even have the same names.
 * Star Trek: Deep Space Nine had two episodes in which Captain Sisko was a science fiction writer in the 1950s, and the other regular characters were his fellow writers, friends, or (as appropriate) enemies.
 * The most famous, but not the only example from that show - there was a holodeck James Bond spoof that played as visions of other selves.
 * "Diabolical!" "Visionary!!"
 * Both Roswell and Smallville have played out forbidden romantic pairings (etc.) by re-telling them in an historical context.
 * Hercules: The Legendary Journeys and Xena: Warrior Princess had a few episodes that used a variant of this, except it was a Flash Forward. The cast members played writers, producers, or various other modern-day characters who worked on the production of the show.
 * At least one of these episodes lampshaded and subverted the idea, with Hercules playing Kevin Sorbo. Including throwing Ares out of a moving car.
 * The old soap opera Dark Shadows had a couple of entire seasons consisting of this.
 * JAG was quite fond of using this with Mac and Harm as the main characters of JAG's past.
 * And David James Elliot always played Harm's father.
 * The series finale of Walker, Texas Ranger includes two parallel stories, one taking place in the present and one taking place in the Old West. They feature the same dozen or so actors playing similar (though not quite identical) characters.
 * Done fairly often on Northern Exposure. One episode featured an old man telling Joel the story of Cicely's founding in 1909. Rob Morrow/Joel Fleischman played Franz Kafka(!) while the other regulars appear as counterpart characters, often with very similar names (Maggie O'Connell, for example, becomes Mary O'Keefe).
 * In the Moonlighting episode "The Dream Sequence Always Rings Twice", Maddie and David hear about an unsolved murder from the 1940s, and then each dream about it that night, putting themselves into the key roles.
 * The It's Always Sunny in Philadelphia episode "The Gang Cracks the Libery Bell" is told in the setting of 1776, with all the characters being their normally horrible, wrong selves (with Cricket as a British general), occasionally making attempts to speak in the vernacular of the day, badly. At multiple points, the characters note that "it's 1776" to justify crime, and the last scene of the story makes it perfectly clear they're all just making it up.
 * MacGyver did several dream episodes along these lines, including a pair of episodes with a period version of MacGyver in the Old West and the two-parter "Good Knight, MacGyver" in which the modern MacGyver imagined himself transported to the days of King Arthur (with Arthur "played" by MacGyver's boss Pete).
 * Press Gang devoted much time to the tempestuous romance of leads Lynda (Julia Sawalha) and Spike (Dexter Fletcher). One episode has a flashback to Spike's parents meeting for the first time - played by Julia Sawalha and Dexter Fletcher.
 * Bones does this in the Season Four finale, with the Jeffersonian being a bar instead of a museum lab.
 * An episode of Lois and Clark had an old security guard tell about how he was betrayed by his girlfriend and business partner, and sent up the river. Cue a flashback with Clark Kent as the young security guard, Lois as the girlfriend, and Lex Luthor as the partner she leaves him for. (This episode was also right before the season one finale, which capped off the Lex/Lois courtship).
 * Stargate SG-1's The Changeling: Is Teal'C in fact an average Earth firefighter? No. But it made for an interesting episode.
 * Stargate Atlantis had Vegas, a CSI-like episode in an alternate universe filmed in Las Vegas.
 * The final season of The Sopranos had Tony hallucinating himself as a salesman called Kevin Finnerty while in a coma.
 * In The X-Files episode "Triangle", Mulder dreams (or did he?) of going back in time on a ghost ship he was looking for, with key characters as the cast of it. Of course, Mulder is still convinced they are all who they really are, and ends up planting a rather passionate kiss on the non-Scully, who gives him a sucker punch to the cheek for his efforts.
 * Also toyed with in the episode where Mulder meets his reincarnating soul mate (unfortunately, she's in a suicide cult). Well, that or she had multiple personality disorder. Under hypnosis, she recalls the details of several of their past lives, which involve several of the show's characters as previous reincarnations as well. One such scenario was described as Mulder and his soul-mate having lost their child (re: his sister) to a drunk driver (re: the Cigarette smoking man), Scully was there too, as Mulder's male best friend.
 * Castle's Noir Episode, "The Blue Butterfly", featured the regular cast acting out a 1940s murder in flashback.
 * Leverage, "The Van Gogh Job"

Webcomics

 * In El Goonish Shive Tedd dreams about one of his alternate universe counterpart's life.
 * So does Ellen, who is given memories of a world where she was born normally. Or Eliot was a girl, which amounts to the same thing.

Western Animation

 * One episode of Kim Possible, "Rewriting History", shows Kim and Ron investigating accusations that Kim's lookalike ancestor, Miriam "Mim" Possible, stole a scientific device about a hundred years ago. As it turns out, Drakken and Shego's turn-of-the-last-century analogs framed her for the deal. It ultimately turns out to be All Just a Dream however. And then they see Ron and Drakken carved on to some poles: apparently, they had gladiators as ancestors waaaaay back in Roman times.
 * Word of God states that despite being just a dream, the ancestors were really existing back when.
 * The Fairly Odd Parents episode "Odd, Odd West" shows AJ's ancestor inventing a computer and Chester's ancestor complaining that no one reads manuals... and "Vicky the Kid" fighting Timmy Turner the Masked Stranger.
 * In the SpongeBob SquarePants episode "Pest Of The West", SpongeBob learns of his great ancestor SpongeBuck SquarePants and how he saved the town of Bikini Gulch from Dead-Eye Plankton.
 * And there was also an episode set in the Middle Ages where SpongeBob and Patrick had to free Bikini Bottomshire from the Evil Sorceror Planktonimor, aided by medieval analogues of Squidward and Sandy.
 * Avatar: The Last Airbender: Zuko's Vision Quest includes a segment with an alternate-him who was never scarred sitting as Fire Lord, with the cold, still Squint Of Evil his father always uses. This is what Zuko thinks he wishes, but it's associated with abandoning his mother and the self-he-is. Ultimately it disturbs him, though not as much as the version who's got Air Nomad tattoos. He is shown feeling his face to make sure the scar is still there and he's awake.