Free Software tools provided by Gnu Projects.
Includes
gcc (Gnu Compiler Collection)
make (Gnu Make)
ld
bzip2
diff (Quick Diff, Diff Algorithm)
patch
arch (Gnu Arch)
...
You can find a more complete list in any GNU ftp mirror.
directory.fsf.org 
(compile the tools yourself, Cee Language)
sourceforge.net (for Microsoft Windows users)
See original on c2.com