MirrorHall creates virtual second monitors over the network using UDP video streaming among Linux desktop or mobile devices. It is optimized for low latency, and is based on gstreamer and GNOME's mutter screen sharing APIs.
Air Display Alternatives
Air Display is described as 'Use your iPad as a wireless display, to extend your Mac desktop. Ever wish you had an extra display for your computer? There’s an app for that! With Air Display, you can use your iPad as an additional monitor for your Mac (Windows no longer supported)' and is a screen mirroring app in the remote work & education category. There are more than 25 alternatives to Air Display for a variety of platforms, including Mac, Windows, iPad, Android and iPhone apps. The best Air Display alternative is Spacedesk, which is free. Other great apps like Air Display are Deskreen, Tab Display, Side Screen and Duet Display.