Linux

Linux is a kernel that is used as the base of Ubuntu, Debian, Fedora, Android, and Remix OS.

Linux OSes
Linux comes in several distributions with their own package managers and other implementations of things. Many Linux distributions include the GNU suite of essential software, however, a notable few (such as Google's Android) omit GNU and instead opt for their own custom suite of software.

Debian and derivatives

 * Debian
 * Devuan GNU+Linux
 * Linux Mint (LMDE)
 * antiX
 * SparkyLinux
 * Endless OS (Debian Stable)
 * Tails (Debian Stable)
 * Q4OS (Debian Stable)
 * PureOS
 * SteamOS (Debian Stable)
 * Corel Linux (Discontinued)
 * KNOPPIX
 * AV Linux
 * Kali Linux (Debian Testing)
 * Parrot Security (Debian Testing)
 * Deepin
 * UOS

Ubuntu and derivatives

 * Ubuntu
 * Kubuntu
 * Xubuntu
 * Lubuntu
 * Edubuntu
 * Linux Mint
 * Ubuntu Studio
 * Mythbuntu
 * elementary OS
 * Linuxfx
 * Peppermint Linux
 * Linspire
 * Zorin OS
 * Linux Lite
 * Ubuntu Kylin
 * Ubuntu Budgie
 * Pop!_OS
 * Ubuntu MATE
 * Bodhi Linux
 * Robolinux
 * Ubuntu Touch

Fedora, Red Hat and derivatives

 * Red Hat Linux
 * Fedora
 * Red Hat Enterprise Linux
 * CentOS
 * Oracle Linux
 * ClearOS
 * Asianux
 * EuroLinux
 * Springdale Linux
 * Fermi Linux LTS
 * Endian Firewall
 * NethServer
 * Rocks Cluster Distribution
 * Baruwa Enterprise Edition
 * Network Security Toolkit
 * Openwall GNU/*/Linux
 * Hanthana Linux
 * BlueOnyx
 * Berry Linux
 * FreePBX
 * OLDPC OS
 * SME Server
 * Qubes OS
 * Miracle Linux

Others

 * PartedMagic
 * Slackware
 * Arch Linux
 * Damn Small Linux
 * Gentoo
 * openSUSE
 * GNOME OS
 * Mandriva Linux
 * Gecko
 * Manjaro
 * Void Linux
 * Tiny Core Linux
 * Android
 * Chrome OS
 * Kogaion
 * Vine Linux

Trivia

 * Linus Torvalds originally meant to call Linux "Freax". One of Linus' coworkers didn't like that name and uploaded the software to the FTP server as "Linux".
 * Linus mentioned when they were about to select the mascot that he was bitten by a penguin one time on a trip to a zoo in Australia. This fact became the inspiration for Linux's mascot.