I’ve started using ProtonMail with the new e-mail address: firstname.lastname@example.org. For now I haven’t switched my existing e-mail address to Proton, but I might in the future. If you have ProtonMail, please use the new address if you are using ProtonMail. Or if you want to try it out, the basic account is free: ProtonMail – Sign Up.
If you want to send PGP encrypted mail from a non-ProtonMail address, use my public key with fingerprint 1B98 E6FD B2E2 3642 D6E3 672C B6E4 147F 87BC 5C70, you can download it here (signature here) or from my public Keybase folder