A Microgame is a type of minigame in the WarioWare series that only lasts a few seconds. It was introduced in WarioWare, Inc.: Mega Microgame$!. In the WarioWare series, all microgames have a genre such as Crazy Cars being in the Introduction game section. There are also boss microgames, which are harder and last longer than regular microgames and are found at the end of each series of microgames. Microgames also can be created in WarioWare: D.I.Y. Also, there are microgames in WarioWare: D.I.Y. Showcase and Game & Wario.
For a complete list of microgames, check Here