Crypho - End-to-end-encrypted messaging and file sharing
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
blockslack.io - Chat for small teams — encrypted and decentralized
Keybase Chat - End-to-end encrypted chat built into Keybase
Wire by EY - A highly secured collaboration platform
aliceandbob.io - A free, light and easy to use client-side PGP tool 🔐