Ripcord - A desktop chat client for Discord and Slack

Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

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

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

Done Hui - No need to switch between multiple pieces of software to get through the workday. CHATS: Communicate freely. CALENDAR: Know your team's availability, plan meetings. No more conflicts. TO-DOs: Stay on top of all projects. FILES: All files, one spot.

Bigtent - BigTent is a web-based organization and communication portal for groups.