An alternate reality game (ARG) is an interactive narrative that uses the real world as a platform, often involving multiple media and game elements, to tell a story that may be affected by participants' ideas or actions.
List
Media with ARG themes or elements
Television
Dispatches from Elsewhere
Westworld
The OA
Films
The Game
Existenz
The Dark Knight
Cloverfield
The Cloverfield Paradox
Super 8
Devour
10 Cloverfield Lane
The Blair Witch Project
The Institute
The Last Broadcast
Ready Player One
The Batman
Short films
This House Has People in It
Unedited Footage of a Bear
Books
Pattern Recognition by William Gibson
Penny Dreadful by Will Christopher Baer
Halting State by Charles Stross
Little Brother by Cory Doctorow
Cathy's Book and Cathy's Key by Sean Stewart, Jordan Weisman, and Cathy Brigg (illustrator) John Dies at the End by David Wong Mr. Mercedes by Stephen King Ready Player One by Ernest Cline This Is Not a Game by Walter Jon Williams Strange Flesh by Michael Olson The Secret: A Treasure Hunt by Byron Preiss S. (Dorst novel) by Doug Dorst House of Leaves by Mark Z. Danielewski