FreeDOS

NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is available for many platforms, including servers, desktops, handheld devices, and embedded systems. The NetBSD project focuses on code clarity, careful design, and portability across many computer architectures. Its source code is publicly available and permissively licensed.

Arch Linux is a Linux distribution for computers with x86-64 processors. The Arch Linux repositories contain both libre, and nonfree software, and the default Arch Linux kernel contains nonfree proprietary blobs, hence the distribution is not endorsed by the GNU project. Arch Linux adheres to five principles: simplicity, modernity, pragmatism, user centrality and versatility. In general, the principles maintain minimal distribution-specific changes, minimal breakage with updates, pragmatic over ideological design choices, user-friendliness, and minimal bloat.

FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular open-source BSD operating system, accounting for more than three-quarters of all installed simply, permissively licensed BSD systems. FreeBSD has similarities with Linux, with two major differences in scope and licensing: FreeBSD maintains a complete system, i.e. the project delivers a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties for system software; and FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux.

Void Linux is an independent Linux distribution that uses the X Binary Package System (XBPS) package manager, which was designed and implemented from scratch, and the runit init system. Excluding binary kernel blobs, a base install is composed entirely of free software, but users can access an official non-free repository to install proprietary software.

Gentoo Linux is a Linux distribution built using the Portage package management system. Unlike a binary software distribution, the source code is compiled locally according to the user's preferences and is often optimized for the specific type of computer. Precompiled binaries are available for some larger packages or those with no available source code. Gentoo Linux was named after the fast-swimming gentoo penguin. The name was chosen to reflect the potential speed improvements of machine-specific optimization, which is a major feature of Gentoo. Gentoo package management is designed to be modular, portable, easy to maintain, and flexible. Gentoo describes itself as a meta-distribution because of its adaptability, in that the majority of users have configurations and sets of installed programs which are unique to the system and the applications they use.

ALT Linux is a set of Russian RPM-based operating systems built on top of the Linux kernel and Sisyphus packages repository. ALT Linux has been developed collectively by ALT Linux Team developers community and ALT Linux Ltd. ALT Linux Team arose from the merger of IPLabs Linux Team and the Linux community of the Institute of Logic, Cognitive Science and Development of Personality. The latter cooperated with Mandrake Linux and SUSE teams to improve localization (specifically Cyrillic), producing a Linux-Mandrake Russian Edition (RE). Mandrake and Mandrake RE became different distributions and thus the decision was made to create a separate project. The name "ALT" was coined, which is a recursive acronym meaning "ALT Linux Team".

OpenBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD. According to de Raadt, OpenBSD is a research operating system for developing security mitigations. The OpenBSD project maintains portable versions of many subsystems as packages for other operating systems. Because of the project's emphasis on code quality, many components are reused in other software projects. Android uses its C standard library, LLVM uses its regular expression library, and Windows 10 uses OpenSSH with LibreSSL. The name OpenBSD refers to the availability of the source code on the Internet. It also refers to the wide range of hardware platforms the system supports.

SteamOS is the primary operating system for the Steam Machine gaming platform by Valve. It is based on the Debian distribution of Linux. SteamOS is designed primarily for playing video games away from a PC (such as from the couch in one's living room) by providing a console-like experience using generic PC hardware that can connect directly to a television. It can run games natively that have been developed for Linux and purchased from the Steam store. Users are also able to stream games from their Windows, Mac or Linux computers to one running SteamOS, and it incorporates the same family sharing and restrictions as Steam on the desktop. Valve claims that it has "achieved significant performance increases in graphics processing" through SteamOS. The operating system is open source, allowing users to build on or adapt the source code, though the actual Steam client is closed.

Manjaro is a free and open-source Linux distribution based on the Arch Linux operating system. Manjaro has a focus on user friendliness and accessibility, and the system itself is designed to work fully "straight out of the box" with its variety of pre-installed software. It features a rolling release update model and uses Pacman as its package manager.