I used to use GnuPG LibrePGP implementation much. For signing and
encryption of files and mail. But nowadays I tend to use much much more
simpler tools like:

=> cmenctool
for file encryption. My own KEKS-codec based creation with post-quantum
hybrid cryptography, parallelised encryption mode and strong passphrase
hardening algorithm.

=> OpenSSH
ssh-keygen for signing files and sometimes Git's tags.

GnuTLS is a TLS library of choice. I am convinced that OpenSSL is one of
the worst software we have got, that should not exist (as the whole
SSL/TLS actually). Go has its own TLS implementation. I use Go GOST TLS
1.3 fork with GOST cryptography support and ChaCha20-Poly1305
ciphersuite as a preference.

=> GnuPG
=> GnuTLS
=> Go
=> Go GOST TLS 1.3
=> GOST