HP-UX

Commercial-grade server-class Unix implementation that complies with all SUS-related guidelines

Xubuntu

Ubuntu-based Linux distro that comes complete with the slick Xfce-4 desktop environment

Tails

Portable operating system with a variety of security and privacy provisions for PC via USB

Apple OS X Mavericks

System software for any late model Macintosh that updates existing machines running 10.8 Mountain Lion

Apple OS X Yosemite

System software package updater and installer for Macintosh computers that run 10.9 Mavericks

Mageia

Linux operating system distribution derived from Mandriva; it is heavily focused on performance and aesthetics

Scientific Linux

Enterprise-grade Linux distro that works equally well on high-performance machines as it does on desktops

Deepin

A beautiful and easy-to-use Linux distribution that's designed with safety and stability in mind

PureOS

A specialized Debian GNU/Linux OS that places a strong emphasis on security and privacy

BackBox.org

Open-source project that seeks to enhance the quality of IT security operations through excellent software