Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is the Unix derivative distributed by the University of California, Berkeley, starting in the 1970s. BSD is one of several branches of Unix operating systems. Here are the BSD systems recommended by PolishLinux.org.
FreeBSDFreeBSD is a free (as in freedom) UNIX-like operating system from the BSD created in 1993. family. Learn more about its features and history. Read more »
OpenBSDA free (as in freedom) UNIX-like system from the BSD family. The founder and leader of the OS is an expert in the computer security domain, a Canadian programmer Theo de Raadt. Read more »
NetBSDA free (as in freedom) UNIX-like system from the BSD family, that first appeared publicly on April 20th, 1993 (NetBSD 0.8). It is recognized for its outstanding portability. Read more »
PCBSDPC-BSD is a fairly new project aiming at making FreeBSD user-friendly by providing a nice default desktop, easy way to install software and graphical configuration tools. Read more »
DesktopBSDDesktopBSD is a brand new BSD operating system with the goal to bring BSD to the masses. It's been founded by an Austian, Peter Hofer. The first testing version has been published in March 2005. After a year, a first stable release appeared. Read more »
If this is not enough, here are some more links that may be interesting for you: