Miko

A miko (巫女) is a shrine maiden in the Shinto religion. Given the strength of Shinto in Japan and the position shrine maidens hold in it, it is no surprise that they are a common character type in anime. Straight portrayals and dramatizations are used just as frequently as a priest or nun would be in North American or European media. If a main character, she might be endowed with mystical powers in order to fight demons, hang Ofuda so that she won't have to fight the demons in the first place, receive visions, etc. Otherwise fictional and non-fictional Miko work in shrines, often as an afterschool job.

Miko are more common in H-Games, because they don't have a permanent vow of chastity; they can just take over their temple when the head priest(ess) dies or quits, and then they can do whatever they want. Japanese depictions of most priestesses and other low-rung religious functionaries tend to borrow from miko, including nuns.

Another reason they are common in H-games and Fan Service-laden anime, however, is that they wear uniforms, and like many other seemingly benign and non-sexualized uniforms, the uniform itself can be a form of Fetish Fuel that is easy to get past the radar. Of course, Shinto is a little less strict about sexuality, so it isn't as sacrilegious as sexualized nuns.

Historically, a miko served as an oracle, offering prophecy in the form of a dance. In real life, most modern Miko will help out with shrine functions such as cleaning, perform ceremonial dances based on the historical versions, offer fortunes (omikuji, those little slips of paper that tell you what your luck will be like), and sell souvenirs, sometimes as a part-time job.

(Not to be confused with that Miko. Or that one. And confusing it with any form of Mako is just stretching it.)

Anime and Manga

 * Mayura of Mythical Detective Loki Ragnarok.
 * Nagasarete Airantou
 * Kamichu! - Matsuri and Miko
 * Kannazuki no Miko - Himeko and Chikane (obviously)
 * Urusei Yatsura - Sakura, who is also the school nurse.
 * Sailor Moon - Rei Hino is a miko at her shrine, which amplifies her spiritual powers. Many of her attacks are Shinto-based, and in civilian form, she can drive off monsters with ofuda. Sailor Moon's creator, Naoko Takeuchi, did miko work in a shrine as a youngster and used her experience as the basis for Rei's character, making this a case of Write What You Know.
 * Ranma ½ - Ukyo Kuonji is shown as an example of the 'parttime/after-school' version in one of the late manga oneshot stories. She presumably only was there a short time or was only a 'casual' miko, as she never displayed any mystical talents during or after that story.
 * Cardcaptor Sakura - Kaho Mizuki
 * Mermaid Melody Pichi Pichi Pitch - In the manga, Rina sometimes fills in for the miko at a shrine devoted to a mermaid spirit.
 * Asagiri no Miko
 * The Simoun Sibyllae in Simoun are treated as mikos (and called that by name), although their religion is quite different from Shinto. Likewise the priestesses of the Plumbum Highlands.
 * Kirara in Samurai 7.
 * Arashi Kishuu in X/1999. Technically, Yuzuriha Nekoi is supposed to become a miko as well, but her grandmother preferred to send her away to school and to fulfill her destiny as a Dragon of Heaven.
 * The Hiiragi siblings in Lucky Star, given that their father is a Shinto priest.
 * Miko are all over Inuyasha in both major and supporting roles, particularly Kikyou, her sister Kaede (also leader of her village), and Midoriko, the "creator" of the Shikon No Tama; Kagome, although not really identified as a miko prior to people in the Sengoku era simply jumping to conclusions, also has many of the powers of a miko, apparently as a result of being Kikyou's reincarnation. There's also an evil miko, Tsubaki, who started as a normal one but was driven to evil over her jealousy against Kikyou.
 * Kagome's family does run what appears to be a traditional Shinto Shrine however.
 * In addition,
 * Miyako from Ghost Hound. At one point she even becomes the prophet for a local cult, although not entirely willingly.
 * Shiho Munakata from My-HiME works part-time at a Shinto shrine with her grandfather, which she and her friends visit in one episode.
 * In the Bonus Episode of Amaenaideyo!!!! the haremettes face off against a group of mikos and a group of Catholic nuns in a game show. While they themselves are often confused for mikos in the West, they are actually Buddhist nuns.
 * In Wagaya no Oinari-sama., Ko is the family sentinel, a miko with powers.
 * Hikaru and Kaoru Midou from Tsukuyomi Moon Phase.
 * Tsumugi in The Mikos Words and The Witches Incantations.
 * Ren-tan from Binchou Tan
 * The epitome of Mikos in the Magical Girl world: Miaka and Yui from Fushigi Yuugi.
 * Silent Moebius - Yamigumo Nami, who wears her outfit instead of a uniform. She fights with holy water and ofuda but later acquires some more powerful weapons.
 * Ayako in Ghost Hunt
 * In Rental Magica miko has a very limited set of abilities, but in this setting the main advantage of Shinto are purification rituals. Thus little Mikan almost exclusively provides cover, but she's very strong in this role and may be the most indispensable member of the team when they face something really nasty.
 * Riza, of Hayate the Combat Butler, is a Miko, though you wouldn't be able to tell except in the chapters where they visit her home.
 * Sabrina, from Pokemon's The Electric Tale of Pikachu manga. This is quite different from her game portrayal as a Jerkass Psychic-type trainer, and her even nastier Nightmare Fuel Station Attendant / Empty Shell Split Personality in the anime.
 * The two Magical Girls of Umi Monogatari are referred to as "Miko of the Sky" and "Miko of the Sea", though only the former's transformed outfit looks like a Miko's (With a miniskirt, which is okay); the latter's is simply a white top and white shortpants.
 * Mikuru Asahina from the Haruhi Suzumiya light novels is forced to dress up as one of these at one point to exorcise some ghosts.
 * Furude Rika in Higurashi no Naku Koro ni is a shrine maiden for a slightly peculiar branch of shinto that includes simulated disembowelment and cannibalism in its ceremonies.
 * Tomoe from Queen's Blade
 * The Harukanaru Toki no Naka de franchise, like Fushigi Yuugi, is centered around two schoolgirls becoming Trapped in Another World to serve as mikos to the local deity (the Yin and Yang side of the Dragon God). They are consistently called mikos, and in the manga/anime adaptations, at least one of them (Akane) has been shown wearing a typical miko outfit at some points.
 * Happy Lesson - Yayoi Sanzenin, also the School Nurse.
 * Yomogi Inaba from Otogi Matsuri; she can see spirits and has inherited a group of five small spirit foxes.
 * Akina from UFO Princess Valkyrie. She also has feelings of inadequacy and attitude problems.
 * Horribly subverted in Mirai Nikki, as the Miko we meet (Tsubaki Kasugano) is not only one of the Diary Holders, but a member  of a Religion of Evil.
 * Mana Tatsumiya from Mahou Sensei Negima, in between the breaks she gets in her mercenary job. This apparently does not conflict
 * Kureha Akabane from Night Wizard The Animation deserves a mention here.
 * Sakuyamon from Digimon Tamers. She has an alternate outfit that is the traditional miko uniform.
 * While far from being an actual miko, the concept of a 'miko chanelling the gods' is stated to have been an inspiration for Rebuild of Evangelion 's Mari Makinami by Word of God
 * Kantarou from Tactics dresses like one but when someone brings it up he denies it, insisting it just happens to be read and white.
 * Akimoto, Misono, Ryouko and Manabe from Jinjya No Susume, a manga that takes a more or less realistic look at running a Shinto shrine and the work Miko do.
 * Shirayuki from Hidan no Aria
 * Madoka from Hoshizora e Kakaru Hashi.
 * Micaiah Chevelle of Magical Girl Lyrical Nanoha ViVid is either one or simply dresses like one for her Barrier Jacket.
 * Sengoku Youko has a miko in the form of Rinzu, though how much she adheres to formal duties are up for guessing, as her adopted parent is a mountain goddess.
 * Akeno from High School DxD is probably a (double?) subversion, she wears the uniform when she uses her strongest magic and is known as the Priestess Of Lightning (in Japanese Miko is used)... but she's also a demon.
 * Mahoro from episode 5 of Mahoromatic dresses as a miko while Suguru and his friends are ghosthunting at their school. Her rationale is just having some fun with the situation.
 * Mahoro from episode 5 of Mahoromatic dresses as a miko while Suguru and his friends are ghosthunting at their school. Her rationale is just having some fun with the situation.

Film

 * Godzilla Vs Mechagodzilla and possibly some other Godzilla films.

Live Action TV

 * Nobuta from Nobuta wo Produce.

Tabletop Games

 * In Dungeons & Dragons 4th edition, the third players handbook adds the Seeker class, which seems based on Miko. They are the equivalent of holy warriors of the Primal Spirits (spirit entities akin to, but separate from, the Gods and Primordials, who embody various aspects of the natural order and the real world, from blood ties to the seasons to specific creatures and placses), who seek out and destroy enemies of the natural order. They use magical powers granted by the Primal Spirits and channeled through bows and throwing weapons to create all kinds of magical effects, such as causing strangling grasses and vines to suddenly erupt from where their arrow hit the ground and ensnare all nearby enemies.
 * In fact, the Seeker was originally intended to be part of a "ki" power source, but the creators realized the Unfortunate Implications in producing a set of classes that shared nothing in common but the "inspired by Asia" background, and so it was broken apart. While the Seeker became a Primal Controller, the Monk, the only other apparent survivor, became a Psionic Striker.
 * In the setting provided in the Mecha Vs Kaiju RPG the intelligence branch of Japan's mecha defense force is made up entirely of Mikos. This makes some sense considering

Video Games

 * Higurashi no Naku Koro ni - Rika
 * Touhou - Reimu Hakurei and Sanae Kochiya
 * Not to be confused with the final boss of Ten Desires, whose name is Miko.
 * The Castlevania Sorrow games feature love interest Mina Hakuba.
 * The title of "Chosen of Mana" in Tales of Symphonia is "Miko" in the original Japanese. The position has religious connotations, although it's more of a Crystal Dragon Jesus religion than anything to do with Shinto.
 * Similarly, the final class of Micaiah from Fire Emblem: Radiant Dawn is called Miko in the Japanese version (But it's read as "Shaman" as a Continuity Nod to Genealogy of Holy War.), though the only Miko-ish things about it are her usage of Light Magic and the color scheme being mostly white and red. And she loses her pantyhose.
 * Nanami from Valkyrie Profile. Hey, if vampires are running around in Norse mythology, why not mikos? Nanami takes a really wrong turn in the afterlife and ends up in Valhalla.
 * Katsumi from Gaia Online, who tends the Shrine at the local Wutai
 * Sayo-chan (a.k.a. Pocky) from the KiKi KaiKai / Pocky & Rocky series of Cute'Em Up games.
 * The Lady Samurai class in Disgaea
 * Mikado in Bushido Blade
 * Maori from Arcana Heart. She has three miko sisters who fight with her, too.
 * Though not being called miko per se, the Fatal Frame series have Shrine Maidens with similar, albeit darker roles. From the first game there were the Rope Shrine Maidens, the second had the Twin Shrine Maidens  , the third had four Handmaidens, also known as Pacifiers in Europe and Japan, that wore full miko attires and performed daily shrine and housekeeping activities, as well as helping  the Tattooed Priestess, another Shrine Maiden  and finally in the fourth game there were the Kanade and the Utsuwa who performed the Rougetsu Kagura ritual to worship the lunar eclipse
 * The fourth game also includes the Tsukimori Shrine Maidens.
 * Torahime from Muramasa: The Demon Blade WAS a Miko in charge of protecting Muramasa. But she is killed before the start of he story and comes back as a horse-riding lady samurai to avenge her family.
 * Ninja Gaiden has a couple of miko: Kureha, who tends the shrine that houses the Ninja Dragon Sword, and Momiji, her sister. Kureha is little more than a Disposable Woman who is barely in the game for two minutes, existing solely so that Ryu can start his Roaring Rampage of Revenge, but Momiji is a Lady of War through and through, using inherited ninjutsu skills to fight rival clans.
 * Mizuki Rashojin from the second Samurai Shodown is a rare villainous Miko, who uses her gohei as a sharp weapon and has a demonic Canine Companion to assist in the fight.
 * Not a character, but Mana Khemia has a costume clearly based on the miko. Amazingly, the recipe to making this costume is in the hands of the resident Cute Ghost Girl.
 * Utsuki and Kureha from Kuon. They are the daughters of the shrine and know how to use Onmyodo, but they are not referred as Miko.
 * Itsuki in Suika, though eventually she realizes that there's no way she could be since she doesn't do the rituals and doesn't remember becoming one.
 * Cloche and Luca from Ar tonelico II: Melody of Metafalica. They are not called "miko" or "shrine maiden" in the US release, but you will hear them referred as such in the Japanese version.
 * Golden Sun: Dark Dawn has Princess Himi, whose default classes all have "Miko" in their names. Oh, and she has the classic red and white outfit as well.
 * Okamiden gives us Miko Cho, whose name should indicate that she is a Miko. Kagu also becomes one, in order to fight off King Fury.
 * Yuna from Final Fantasy X isn't a miko, but she has a very important place at her temple and her outfit - with its plain white top, long drapey white sleeves, large bow at the back, and long, pleated skirt - is clearly based on a miko outfit.
 * Mousehunt has the Sacred Shrine Mouse, a mouse with a shrine maiden outfit, talismans and gohei.