There are no illegal sources for downloading operating systems that are available for sale commercially, found below. The links are for my convenience in locating the download location, for a specific distribution, or version, quickly and easily. If there is a version of an operating system that you can use below, I am glad I could help. Enjoy!
If you can download your desired distro via torrent, it is highly suggested that you do so. If you have a high speed internet connection, you can easily get the distro you want at remarkable speeds, and if you have a hosted dedicated server somewhere, even more so!