Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
File Encryption XP - A program designed for protecting confidential information stored on your computer.
YAATA - YAATA app offers features that let you send multimedia files such as images, videos, audio, and GIFs, etc.
Chatlink.com - Anonymous communication platform
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
Autocrypt - Convenient End-to-End Encryption for E-Mail