Remote Mouse - Turn your smartphone into a wireless touchpad and keyboard now!
Softros LAN messenger - LAN messenger for an internal office chat for home or business users. It does not require a server and is very easy to install and use. It supports personal chats, group chats, message brodcasting, files transfer and remote desktop access.
KDE Connect - Integrate Android with the KDE Desktop
MyChat - Secure instant messenger for any network
Monect - Make the best use of sensors on smart device to control PC, simulate steering wheel, game-pad...
BORGChat - BORGChat is a LAN messaging software program.