Displays
The complete toolbox to manage your monitors
14 Alternatives To Displays
AirBeamTV
Application to mirror the screen and sound of your Mac to Smart TV or Chromecast.
Axon M
Add a 2nd folding screen to your phone
DUO by Mobile Pixels
A second screen for your laptop
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.
Duet Pro
Turn your iPad Pro Into a high performance drawing tablet
Le Slide
Easily add two more monitors to your laptop í ½í²»
Mountie+
Connect a second (or third) screen to your laptop
Padbury Clock Screensaver
Minimal screensaver for Mac
Samsung DeX
Connect your Galaxy S8/S8+ to a monitor
ScreenFocus
Working with multiple monitors made right.
Screens
GNU Screen.
TouchBar for your old MacBook
Use Touch Bar on an iPad through USB connection
Vinpok Split
Best on-the-go touch screen 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.