Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Crypho - End-to-end-encrypted messaging and file sharing
Talla the Task Assistant - A.I. task-list manager built for Slack
blockslack.io - Chat for small teams — encrypted and decentralized
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Wire by EY - A highly secured collaboration platform