Signature Colors

One of the easiest ways to make a character stand out is to heavily associate them with a color. Sure, a distinct appearance and likable personality are far more important since a good character needs substance, but color association can go a long way in making somebody stand out in the viewer's mind. Hair color, clothing, favorite foods, and special weapons are just some of the many ways Signature Colors can be applied to a character. They also play a big role in fleshing out factions: whether it's something as mundane as a sports team or frat house, or something far grander like a militia, country, or a criminal organization, it's a safe bet that there will be a special color or combination thereof that said faction will claim as their own.

This is usually an in-universe trope, where the color scheme is self-enforced by the characters as opposed to 'just' the artists. Settings with Elemental Powers will often have signature colors for each element commonly worn by their wielders.

When signature colors are applied to an entire nation, they're sometimes the colors of the nation's flag - for example, the "red white and blue" color scheme that's found across the United States of America.

This is a subtrope of Color-Coded for Your Convenience, and Supertrope of Color-Coded Wizardry and Color-Coded Patrician.

Anime and Manga

 * Unless she's in school uniform or kimono, Rin Tohsaka of Fate/stay night is consistently shown in official art wearing red and black. Even her official bikini is red. (Some scenes in Fate/Zero show her wearing red and white, showing that her accent colour has changed over time.)
 * Each of the main characters in K-On! has a signature color: Yui's Red, Mio's Blue, Ritsu's Yellow, Mugi's Pink, Azusa's Teal, Ui's Orange, Nodoka's Light Green, and Jun's Light Blue.

Fan Works

 * In chapter 4 of Drunkard's Walk S: Heart of Steel, Usagi and Ami buy workout outfits for their training sessions with Doug -- in exactly the same color schemes as their Custom Uniforms as Sailor Moon and Sailor Mercury. Luna buys a tracksuit in the color scheme of her canon sundress, as well. Doug considers lecturing them about taking this trope too far, citing the trope by name.

Literature

 * In The Chronicles of Amber Amberites and related characters have "their" colors:
 * Dworkin: purple and orange.
 * Oberon: green and gold
 * Corwin and Deirdre: silver and black.
 * Eric: black and red.
 * Benedict: orange, yellow, brown.
 * Bleys: red and orange.
 * Brand: green.
 * Caine: black and green.
 * Delwin: brown and black.
 * Flora: green.
 * Gerard: blue and gray.
 * Julian: White.
 * Llewella: gray and green
 * Random: orange, red, brown.
 * Dalt: green and black.
 * Rein: crimson.
 * In Grandmaster of Demonic Cultivation the different cultivation clans have each a color scheme:
 * Gusu Lan: white and light blue. In the TV adaptation The Untamed, they make the visiting students dress in white clothes with their own sect color accents.
 * Lanling Jin: yellow and gold.
 * Yunmeng Jiang: purple.
 * Qishan Wen: red.
 * Qinghe Nie: brown and green. The animated adaptations and the manhua make them wear more green, while The Untamed puts them in a purplish gray.
 * Wei Wuxian, the protagonist, despite being (initially) affiliated to Yunmeng Jiang, is more identified with red and black - in the book it begins after he becomes a demonic cultivator, but in the adaptations he is put in black robes way before that.
 * In The Lord of the Rings, Gandalf "The Grey" always wore grey robes. After his return as Gandalf the White and slight personality change, he wore only his white robes.

Live-Action TV

 * WandaVision: All over the place, once the show leaves the black-and-white era.
 * Agnes always wears something purple.
 * Wanda frequently wears red, the color of her magic. Even her car is red.
 * The Mind Stone. its energy, and related powers, are yellow.
 * Billy always wears red and Tommy always wears blue and/or green -- which correspond to the colors of their comic book counterparts' costumes.

Video Games

 * Yggdra Union has it as an Identical Twin ID Tag: Aegina's favorite color is red, Luciana's favorite colors are black and blue.
 * When creating a super group in City of Heroes, among the decisions to be made is a primary and secondary color, which the members of the group can choose to have automatically replace the existing colors of their costumes to indicate they are on super group business. (Or are just loyal members.)

Web Comics

 * Girl Genius:
 * Tarvek usually wears dark red and white.
 * Bang wears bright red (presumably to not look bad with blood, except in this case not her blood) and white.
 * Martellus has at least one light golden piece on him, sometimes clothed almost entirely in such hues.
 * Albia usually wears white, except her gardening suit (this may also serve to underscore the "unofficial" status of that audience).
 * Princess Neena may be in her pajamas, fancy dress for a theme ball or in pants, blouse, corset and jacket when going about her daily business… but the cloth is always slightly greenish blue, and accessories (if any) are bright golden.

Web Original

 * Huntsmen and Huntresses in RWBY appear to have signature colors. It's more pronounced in the main characters -- Ruby's red and black, Yang's brown and saffron, Weiss's white and pastel blue, Nora's pink and white -- but it appears to be present in the stylings of the older generation as well.  Ruby and Yang's father, Taiyang Xiao Long, seems to have a similar color scheme to Yang's, for instance.

Western Animation

 * Shego from Kim Possible is never seen not sporting anything green, even when in disguise.
 * Same goes for her brothers, the members of the Superhero group Team Go, who each have a signature colour.
 * The Elemental Nations and their respective benders in the Avatar Universe each have a different signature color, and combine this with Color Coded for Your Convenience.
 * The Water Tribes are all about blue with white accents. The only exception are Swamp benders, whose few clothes are brown.
 * The Fire Nation favors reds with gold accents.
 * The Earth Kingdom citizens dress in a variety of greens with the occasional brown.
 * The Air Nomads wear orange and yellow.