Xibo - Digital Signage for Everyone!
Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Yodeck - Yodeck enables you to design and schedule your digital signage on Raspberry Pi easily from the web, using your computer, tablet or smartphone.
Ripcord - A desktop chat client for Discord and Slack
TelemetryTV - Powerful and Intuitive Cloud-Based Digital Signage Software That Lets You Easily Manage Content on Screens
Ziggs - Smoothly Share Content Between Devices!