The distribution of Linux includes both commercial and non-commercial categories.
Non-commercial versions are available in the following ways:
CentOS: Emulate Red Hat Enterprise Linux.
debian:www.debian.org
Fedora:red Hat Company's community version.
Opensuse:suse free release of Linux.
Ubuntu: Similar to Debian's free hair version.
Commercial versions are available in the following ways:
Gentoo: A release version based on source code compilation.
Mandriva: The first Linux distribution to be designed for non-technical users.
The Enterprise-class commercial Linux distribution of the SUSE Linux Enterprise:novell company.
The Enterprise-class commercial release of Red Hat enterprise:red Hat Corporation.
Red flag: The best Linux development in the country.
Turbolinux: A successful release in China and Japan.
This article from "Technology is Strength" blog, declined reprint!
What are the Linux distributions?