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
Expensive Chat - Chatroom where you pay per letter
blockslack.io - Chat for small teams — encrypted and decentralized
200 Words a Day - A community to get into a writing habit and improve ✍️
Wire by EY - A highly secured collaboration platform