Crypho - End-to-end-encrypted messaging and file sharing
blockslack.io - Chat for small teams — encrypted and decentralized
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Wire by EY - A highly secured collaboration platform
Confide - On the off chance that you need to get your messages private and encoded then utilize Confide that will fill in as your own and classified courier.
GrapheneOS - GrapheneOS is an open source privacy and security focused mobile OS with Android app compatibility.