Linux: Linux Distributions
This article lists the Linux distributions.
GNU/Linux Distribution Timeline
GNU/Linux Distribution Timeline is a cladogram of GNU/Linux distributions, placed on a timeline. The project started in 2006 and currently lists almost 500 distributions. The following figure is GNU/Linux Distribution Timeline 12.10, you will get more detail information when you open the figure and click the name of specific distribution.
DistroWatch.com
If you want to know all information for all of those different linux distributions in one place, the website DistroWatch is what you need.