Remote Mouse - Turn your smartphone into a wireless touchpad and keyboard now!
TeamViewer - TeamViewer lets you establish a connection to any PC or server within just a few seconds.
KDE Connect - Integrate Android with the KDE Desktop
mRemoteNG - mRemoteNG is a fork of mRemote, an open source, tabbed, multi-protocol, remote connections manager.
Monect - Make the best use of sensors on smart device to control PC, simulate steering wheel, game-pad...
join.me - Instant screen sharing. Instant Aha!