Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
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.
Pushbullet - Pushbullet - Your devices working better together
MyChat - Secure instant messenger for any network
AirMore - AirMore is a cross-platform toolset that can help you manage any Android device wirelessly.
BORGChat - BORGChat is a LAN messaging software program.