Duet Display - With Duet Display, you can transform your iPhone or iPad into a second display to expand the screen space of your PC or Mac system.
Vysor - Vysor lets you view and control your Android on your computer.
Luna Display - Hardware that turns the iPad into a wireless second display
Samsung DeX - Connect your Galaxy S8/S8+ to a monitor
iDisplay - iDisplay is an app that turns a mobile device into a secondary desktop monitor. The app currently supports iOS, Android, Windows and MacOS, and it lets users connect a desktop computer to a mobile device over WiFi. Read more about iDisplay.
ApowerMirror - ApowerMirror is a wireless screen mirroring app that allows streaming of your Android or iOS device to any Mac or Windows computer. Android and iPhone devices can also be controlled when mirrored to a PC