Apps similar to MacDisplay include Spacedesk, which has a free version. Other options are Side Screen, Deskreen, Tab Display and Duet Display. You can choose from more than 10 Screen Mirroring Apps like MacDisplay for Mac, Windows, iPad, iPhone and Android.
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)
United States
Turn your iPad/iPhone or Android tablet or smartphone into a convenient side monitor for your Windows or Mac desktop. iDisplay is a universal app specially optimized for iPad, iPhone, iPod Touch, and Android devices screens.
Germany
EU
Smart devices become monitors by connecting them to a PC via USB! The Convenient Connect TwomonUSB
United Kingdom
Uses local Wi-Fi, Ethernet, or Thunderbolt Bridge to add a Mac, Windows PC, or Android device as extra Mac desktop space, or mirror screens on supported computers. It is free, needs no account, subscription, dongle, or cloud relay, and is for trusted networks.
Taiwan
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.
