Quattro Adventure, Quattro Arcade, and Quattro Sports are a series of unreleased games for the Nintendo Entertainment System, distributed in the USA. The "Unl" designation indicates an unlicensed nature.   Details on the actual gameplay mechanics of these games are unavailable; however, the names hint at varied genres, including adventure, arcade-style action, and possibly sports simulations.  The lack of official releases and information hinders a detailed historical and gameplay overview. The games' creators remain unknown.

Quattro Adventure (USA) (Unl)

Qix (USA)