KeePass - KeePass is an open source password manager. Passwords can be stored in highly-encrypted databases, which can be unlocked with one master password or key file.
KeePassXC - KeePass Cross-Platform Community Edition - A community maintained fork of the popular KeePassX...
Passbook - Password manager for GNOME desktop, Gnome Keyring Manager and Viewer
Seahorse - Front end for GnuPG.
bitwarden - Bitwarden is a free and open source password management solution for individuals, teams, and business organizations.
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.