A full Web-based phone and fax solution that integrates the best-of-breed open source VoIP software

AMIGO Linux is one of the easiest ways yet to run Linux. Just unzip on a FAT partition and boot. No installation needed.

Anubis-Linux is a distro that's designed to provide a lot of development tools and documentation.

Arch Linux is an i686-optimized Linux distribution based on ideas from CRUX.

ArchPwn is a security based Linux Live CD/DVD system that aims to be a fully working swiss army knife for pentesting purpose (GPL licensed).

Arco-debian is a bootable CD Linux with automatic hardware detection is originally based on Knoppix and Kurumin.

BasicLinux is a multipurpose mini-Linux that boots from HD, FD or CD-ROM.

Bayanihan Linux is a complete open source-based desktop solution for office and school use. It is a package that includes an operating system, a word processor, spreadsheet program, presentation software, email facility, an internet browser, and a graphics editor.

Bio-Linux is an Ubunto based Linux distribution created for scientists to use in analyzing biological data. 

BitCurator contains free and open source digital forensics tools and associated software libraries.

BlackArch Linux is a penetration testing Linux distribution based on Arch Linux and designed to be by penetration testers and security researchers. 

Black Lab Linux is based on Ubuntu and contains packages for multimedia production, content creation, and software development as well as support for some popular browser plugins.

Burning Thunder Pup is a Puppy Linux distribution with (working) Firefox and Thunderbird desktop icons and Wine in the terminal.

BLAG is a Linux distribution based on Fedora Core and reduced to one CD. It includes useful applications missing from Fedora Core (e.g. mp3, p2p, apt, etc…), as well as a suite of graphics, Internet, audio, video, office, and peer-to-peer file sharing applications.

CDlinux is a compact distribution of GNU/Linux. The name is a synonymous of “Compact Distro Linux.” It is small in size, yet rich in features. 

The CentOS Project is a community driven Linux project that provides two different Linux distributions. CentOS Linux is a consistent and stable platform. CentOS Stream is a rolling release distribution that runs just before Red Hat Enterprise Linux (RHEL).

Damn small Linux is a very small live CD Linux distribution. It has a working desktop environment yet is small enough to fit on a business card-size CD.

Linux DaVinci is an operating system based upon Slax, which permits to develop and fulfill Italian schools necessities about computer science course into college schools.

Debian is a Linux based operating system that includes over 50,000 additional packages.

Dragora GNU/Linux is a new, independent distribution made in Argentina. 

Dyne:bolic GNU/Linux is a live bootable distribution working directly from the CD without the need to install or change anything on harddisk

EasyOS is an experimental Linux distribution with a number of features that set it aside from other distributions, it is designed to support containers, it can run totally isolated if desired, the user is root, atomic version upgrade, supports SFS packages, GUIs for everything.

The Elemental Linux Server (ELS) is designed from the outset to be a minimal, no-frills server distribution. There is no GUI, everything is console-based. 

Epidemic GNU/Linux is a Brazilian Live-CD Linux Distribution based on Debian. The focus is the desktop use.

ESUN Linux is an Ubuntu-based distribution containing free software for enterprise management.

Fatdog64 is an all 64bit distro built using T2 build scripts and Woof (Puppy) init scripts.

The Fedora Project is a Red-Hat-sponsored and community-supported open source project, though it is not a supported product of Red Hat, Inc.

FortMacTux is a small, fast, and full featured KDE/Slackware-based, Slax forked, Linux distribution. It was inspired by and for AlbertA.

Funtoo is a variation on Gentoo Linux.

Generations Linux is a bootable ISO live GNU/Linux operating environment. The ISO9660 image file can be used to burn a CD-ROM or used with virtualization products such as VMware Player or VirtualBox. 

Gibraltar, a Debian GNU/Linux based firewall distribution, available for download. This Gibraltar does not need to be installed on a hard disk but can be run directly from the bootable, live CD-ROM. 

GoboLinux is a Linux distribution that breaks with the historical Unix directory hierarchy. Basically, this means that there are no directories such as /usr and /etc.

Granular is a Linux Operating System that is intended to be as user-friendly and flexible as possible.

Hamux is based on CentOS Linux and provides packages for Ham Radio.

Hanthana is a Linux based operating system and a Fedora remix suitable for desktop and laptop users.

KNOPPIX is a bootable CD with a collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices and other peripherals. 

Knoppix-NSM is dedicated to providing a framework for individuals wanting to learn about Network Security Monitoring (NSM) or who want to quickly and reliably deploy a NSM capability in their network.

LadyBug is a french GNU/Linux Live System base on PCLINUXOS and SAM.

Linux Mint is based on Debian and Ubuntu. It's a safe and reliable Linux that is designed to be modern, elegant, comfortable, powerful, and easy to use.

LinuxShark is based on opens use 11.2 and The Linux Kernel Version 2.6.32.2, It is regularly updated with the latest security patches and Kernel upgrades.

The LNX-BBC is a mini Linux-distribution, small enough to fit on a CD-ROM that has been cut, pressed, or molded to the size and shape of a business card.

Mageia is a GNU/Linux based free software operating system that is run as a community project and supported by a non-profit organization.

Manjaro Linux is an accessible, friendly, open-source Linux distribution and community.

MEPIS Linux is a Debian-based desktop Linux distribution designed for both personal and business purposes.

MyDebian is Debian Live based Live Linux distribution. 

Net Linux is remastered and pre-configured Linux 4.31 with Firefox and Skype

oniondsl is a live CD based on Damn Small Linux which is set up to automatically bypass the Australian Internet censorship program.

The OpenMandriva Association's goal is to develop a pragmatic distribution that provides the best user experience for everyone, from newbies to developers. 

The openSUSE project is a worldwide community program sponsored by Novell that promotes the use of Linux everywhere. 

Openwall GNU/*/Linux (or Owl for short) is a security-enhanced operating system with Linux and GNU software as its core, compatible with other major distributions of GNU/*/Linux.

PCLinuxOS is an English only live CD initially based on Mandrake Linux that runs entirely from a bootable CD.

The PCPAC project describes a method for converting a Linux desktop distribution into a safe, reliable and efficient PAC, a Public Access Computer, for a library, school or waiting room.

pdaXrom is a cross-platform Linux distribution with own build system. Its targets are PDA and embedded systems. 

Peanut Linux is a Linux OS (O)perating (S)ystem.

A Portable Linux Operating system that you can bring with you on a USB hard drive, flash pendrive, thumbdrive, flashdrive, ipod, phone or other mobile device. Project is no longer under active development.

What is poly-p-ux? Well, just take a look at the image on the main page. (sorry, lynx users :D ). Say you have a VERRY old computer (386, 486, or Pentium, ideally.). Think of it as a snail. It can't do much. In fact, you probably have Windows 3.1 on it right now. Admit it. Well, poly-p-ux is a Linux distribution that's your own little rocket.

Puppy Linux is a Live CD Linux distribution that is very small and focuses on ease of use. If the computer has at least 256 MB of RAM, the entire operating system and all the applications will run from RAM, allowing the boot medium to be removed after the operating system starts. 

PuppyRus Linux is a Russian version of Puppy Linux.

A variant of puppy, Quirky is a Linux distribution and is in the “Puppy Linux family”, also known as a “puplet”.

Refracta is a variant of the GNU operating system and uses the Linux kernel. 

Knoppix-Based Linux LiveCD for robotics hobbyists.

ROOT is a GNU/Linux operating system aiming for speed, simpleness and flexibility. It contains many high quality software packages for both server and workstation use.

Sabayon Linux is an operating system powered by the Linux kernel and GNU.

SliTaz is a free operating system, working completely in RAM and booting from removable media such as a cdrom or USB key.

The SME Server is an open-source software package that, when installed on a PC-compatible computer, transforms it into a easy-to-use, Linux-based communications server.

SoL is short for Server optimized Linux and is a Linux distribution completely independent from other Linux-distributions.

Source Mage is a source-based GNU/Linux distribution based on a Sorcery metaphor of “casting” and “dispelling” programs, which we refer to as “spells”, and a package manager called “Sorcery”.

The StartCom Linux operating systems are based on the Red Hat Enterprise and Fedora source code, each modified with reliability, security and efficiency in mind, to fit the tasks assigned to each flavor of StartCom Linux.

T2 started as a community driven fork from the ROCK Linux Project with the aim to create a decentralized development and clean a framework for spin-off projects and customized distributions. Another goal was to provide a more continous release stream for stable security updates.

Tiny Core Linux is a very small (10 MB) minimal Linux Desktop. It is based
on Linux 2.6 kernel, Busybox, Tiny X, Fltk, and Jwm.

TinyMe is a remaster of PCLinuxOS. It comes packaged in a miniscule 200MB or smaller ISO. We do this for those of you who have old computers, like to mess around with small/fast systems, or just want a minimal environment. 

Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things

Originally Unity-Linux was a Mandriva based Linux distribution that was started when a number of packagers left PCLinuxOS. Due to multiple differences both parties thought it best to part ways, so Unity-Linux was born.

Vector Linux is a small, fast, Intel Linux operating system based on one of the original Linux distributions, Slackware.

XCP-ng is an open source hypervisor based on XenServer

Zenarch is a hybrid/modular live cd based on slax and archlinux OS.

Zenwalk is a GNU/Linux operating system, designed to provide the following characteristics:
Modern and user-friendly (latest stable software, selected applications); Fast (optimized for performance capabilities); Rational (one mainstream application for each task); Complete (full development/desktop/multimedia environment); Evolutionary (simple network package management tool – netpkg).