Some ideas for useful addons to existing projects, keeping in mind I am not sure what your focus as a front-end developer is:
Gnu Privacy Assistant https://www.gnupg.org/related_software/gpa/index.html is a GnuPG frontend written in GTK. The software works well and does nice things like file encryption, taking a piece of text and outputting it encrypted.
The GUI badly needs improvement. I'd be happy to point out several problems.
I also don't believe GPA is available in platforms like Windows and macOS.
Kleopatra is a GnuPG and S/MIME frontend written in Qt (KDE libraries). It is maintained and available on Windows (through GPG4Win) but is still "computer power user"-centric and could also use user interaction love.
Enigmail https://www.enigmail.net/index.php/en/ - Also has several pain points that might be interesting to solve.
On a side note: One method that Enigmail uses to import PGP certificate is the ability to get a valid PGP certificate from a URL. Adding that functionality to GPA and Kleopatra would be nice wins.
All three frontends, Enigmail, Kleopatra, or GnuPG would do well to have a graphical or screen-based export of public keys. Something like a QR-code export of a minimal PGP public key would be nice for importing via smartphones.
Gnu Privacy Assistant https://www.gnupg.org/related_software/gpa/index.html is a GnuPG frontend written in GTK. The software works well and does nice things like file encryption, taking a piece of text and outputting it encrypted.
The GUI badly needs improvement. I'd be happy to point out several problems. I also don't believe GPA is available in platforms like Windows and macOS.
Kleopatra is a GnuPG and S/MIME frontend written in Qt (KDE libraries). It is maintained and available on Windows (through GPG4Win) but is still "computer power user"-centric and could also use user interaction love.
Enigmail https://www.enigmail.net/index.php/en/ - Also has several pain points that might be interesting to solve.
On a side note: One method that Enigmail uses to import PGP certificate is the ability to get a valid PGP certificate from a URL. Adding that functionality to GPA and Kleopatra would be nice wins.
All three frontends, Enigmail, Kleopatra, or GnuPG would do well to have a graphical or screen-based export of public keys. Something like a QR-code export of a minimal PGP public key would be nice for importing via smartphones.