Please, consider adding Planck Security for Privacy Email and File Encryption

[GLPlanck]

https://www.planck.security/planck

Planck provides email encryption, signature and sender authentication, as well as standalone file encryption.
It is built upon the principles of PGP and public/private cryptography, using modern cipher suites (AES256 and RSA4096) and state-of-the-art opensource core crypto libraries (Botan and SequoiaPGP).
No third party is involved in trust management.

While paid features and support are available for the enterprise, the email and file plugin and native apps are available for free.