Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Facebook - Connect with friends, family and other people you know. Share photos and videos, send messages and get updates.
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.
X (Twitter) - Connect with your friends and other fascinating people. Get in-the-moment updates on the things that interest you. And watch events unfold, in real time, from every angle.
Ripcord - A desktop chat client for Discord and Slack
Mastodon - Mastodon is a decentralized, open source social network. This is just one part of the network, run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome!