Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
Ripcord - A desktop chat client for Discord and Slack
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.
Ziggs - Smoothly Share Content Between Devices!
RingCentral Video - Live life unlimited. Free video meetings and team messaging in one app that works the way you do.