Slack - A messaging app for teams who see through the Earth!

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.

Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.

MyChat - Secure instant messenger for any network

Microsoft Teams - Microsoft Teams provides the enterprise-level security, compliance and management features you expect from Office 365, including broad support for compliance standards, and eDiscovery and legal hold for channels, chats, and files.

BORGChat - BORGChat is a LAN messaging software program.