WeTime - No more back and forth between Gmail and Google Calendar, schedule your meetings from within your...
Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Ripcord - A desktop chat client for Discord and Slack
OpenSondage - Make your polls with OpenSondage.
Ziggs - Smoothly Share Content Between Devices!