The Minish are a species found in The Legend of Zelda: The Minish Cap for the Game Boy Advance. As their name implies, they're a race of very tiny people that an adult Hylian would not be able to see. They're also known as Picori, which they are called by the people of Hyrule.
Apparently a Picori is no bigger than the thumb of Link. When the green-clad Link dawns the Minish Cap, he'll shrink to the miniature size of the Minish.
In the game their are three different clans of Minish, consisting of the forest Minish, the mountain Minish, and finally the town Minish. Each are clothed in different garb and act differently from one another.
The Mountain Minish are, according to the game, a group (seven) of the species that followed Melari to Mount Cernel. They live within the mountain and dig for Kinstones, and will be encountered by Link early in the game. They are a peaceful species and some consider them to take the place of the Gorons, who comparably also lived within a mountain and acted similarly.