Power Trio/Sandbox

Three is a common number in ensembles. Any show or other work is likely to have no more than three main characters. More than that and the work risks a lack of Character Development, unless it manages to be a Long Runner. Even in works with a large number of protagonists, there will almost always be up to three main characters with the remainder having supporting roles. On the bad guy side, three is usually the largest that a group of villains can find themselves in while still remaining threatening individually. Villainous groups of more than three can risk being Elite Mooks who rely on numbers. As with the heroes, villains can have any number of supporting minions and henchmen but there will rarely be more than three major villains working together. As a result, the three-character group has a number of tropes based on it. A group of three in general is a Power Trio.

There are two main ways to have a Power Trio dynamic. The first and probably most common is to have two members of the group be each others Foils, coming into conflict with each other. The third member of the group acts as the mediator, keeping the team together and balancing their respective personalities. The mediator is very often either a strong leader or a caring, maternal spirit, or both. The second method is to have a balanced trio, with each member contributing and conflicting equally with each other, or simply having three parts of a single unifying theme.

See also Triang Relations, which often form, as well as One True Threesome, which is a common fan reaction. Three Plus Two is a Power Trio within a Five-Man Band. A Six-Student Clique is often broken into two Power Trios and a Magnificent Seven Samurai often has one, and sometimes two, Power Trios of its own.

No examples please. Examples should go in one of the subtrope pages.

Note that few of these tropes step on each others toes. It's more than possible for a three-character ensemble to have more than one of these tropes apply to it.
 * Beauty, Brains, and Brawn: The Chick, The Smart Guy and The Big Guy.
 * Blonde, Brunette, Redhead: Hair colors. Usually results in the Dumb Blonde, Brainy Brunette and Fiery Redhead.
 * Comic Trio: An idiot that comes up with stupid plans, another idiot who blindly follows instructions and a relatively normal person who can't do anything to stop them.
 * Freudian Trio: The three characters represent the Ego, Superego and Id of Freudian Psychology with the foils presenting the intellectual and emotional viewpoints and the third character balancing the two, usually having to Take a Third Option that satisfies them both.
 * The Hecate Sisters: Three female characters representing the maiden, mother and crone.
 * Terrible Trio: A villain with two henchmen; usually Played for Laughs, the villain is never the Big Bad.
 * Three Amigos: The Hero, a friend of the same gender and a friend of the opposite gender.
 * Three Faces of Eve: Three female characters representing the child, the mother and the seductress.
 * Token Trio: White male, white female and a male of a visible minority.
 * Two Guys and a Girl: The Hero and The Lancer, mediated by The Chick.
 * With a Friend and a Stranger: Male center, joined by a childhood friend and a girl from out of nowhere.