Red shows up a lot when it comes to the heroes of a story, usually the color of their clothing. As their main color motif, it could also be their hair color, gear, Battle Aura, or body parts for robots and non-human characters. This could be limited to the main protagonist or be as wide as an entire Badass Army. Some Chromatic Arrangement trios have the leader wear red.
The reason is that red is the color of fire and blood, hence the color of action. Thus it conveys that the heroes are people of action as well (regardless of exactly how the heroism is presented in the show).
In Japan, this was traditional in old Kabuki plays and the like. It's made to represent the hero bathed in the blood of his enemies. It is much less common in America due to the association with red as the color of the country's enemies (redcoat British in the Revolutionary War, Red Scares and the Cold War in the 20th century), but gets a pass if it's paired with white and/or blue.
Keep in mind that since not all heroes wear red (for example, Blue is also very common), and other characters don't avoid that color, there isn't much point in listing aversions to this.
A Super-Trope to Primary-Color Champion and Pink Heroine. A Sub-Trope of Good Colors, Evil Colors. A Sister Trope to Fire Is Red, Blue Is Heroic and Good Wears White.
Compare Heroes Want Redheads, Bring My Red Jacket, Heroes Prefer Swords, Color-Coded Characters, Purple Is Powerful, Law of Chromatic Superiority, Satan Is Good, and Red Oni, Blue Oni.
Contrast Red and Black and Evil All Over, Red Eyes, Take Warning, Evil Redhead, Big Red Devil, a literal Red Shirt (and Red Shirt Army), Char Clone, Evil Wears Black, Green and Mean, Little Dead Riding Hood.
Compare AND contrast Red Is Violent, which is sometimes used as its Evil Counterpart and sometimes its Good Is Not Soft counterpart. (In the latter case, expect overlap.)
