I don't know why TOX is not more popular. How can you go wrong with encrypted Peer to Peer? As for Email I have been using Betterbird as an email client and Macaw.me as my email. The Betterbird is awesome! It simply handles PGP with Protonmail. Seamlessly resolves PGP encryption and even looks up the keys on Protonmail. The Protonmail users simply need to import your PGP key and you can have full encrypted email for free.