Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited

Drift - A messaging app that helps you grow your business.

Ripcord - A desktop chat client for Discord and Slack

Slack for Mac - A new, improved Slack desktop app for Mac

Ziggs - Smoothly Share Content Between Devices!