VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
KeePassXC - KeePass Cross-Platform Community Edition - A community maintained fork of the popular KeePassX...
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Windows BitLocker - This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.
Strongbox by Phoebe Code Limited - Strongbox began as a side project because there were no password managers on iOS that supported the Password Safe file format. Password Safe was one a leading password manager for Windows and was initially created by cryptographer Bruce Schneier.
TrueCrypt - TrueCrypt is a leading cross-platform that provides encryption tools that allow you to migrate any encrypted data to virtual disks images on your systems.