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

Framadate - Make your polls

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.

Dudle - Dudle is an online scheduling application, which is free and open source.

Ripcord - A desktop chat client for Discord and Slack

Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.