PNGOUT / KZIP license
http://www.advsys.net/ken/utils.htm#pngoutkziplicense

The command line versions of PNGOUT.EXE and KZIP.EXE are free, as are the Mac and Linux ports. You may use PNGOUT- or KZIP-compressed content for non-commercial or commercial purposes.

Redistributing, repackaging, or reusing the PNGOUT or KZIP executable is prohibited without the express consent of Ardfry Imaging, LLC, and a formal business agreement.