Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Ripcord - A desktop chat client for Discord and Slack
Weavy - The complete white-label framework for in-app team messaging and collaboration.
Ziggs - Smoothly Share Content Between Devices!
Zangi Business Solutions - Zangi Business Solutions is a platform that offers secure and private communication such as IM, calls, conferences, and file sharing on one unified platform.
Protonet SOUL - Protonet SOUL is social project management and collaboration for workgroup communication, file sharing, and task management.