ComClear: A history cleaner for Netscape Navigator and Communicator. (C) [GNU/Linux, Unix, Windows]
Emacs/W3: A web browser that runs under GNU Emacs.
Galeon: A GNOME web browser based on the gecko layout engine.
K-Meleon: A Windows web browser based on the gecko layout engine.
Konqueror: A web browser with HTML4.0 compliance, supporting Java applets, JavaScript, CSS1 and (partially) CSS2, as well as Netscape plugins. (C++) [GNU/Linux]
Mirror: Duplicates a directory hierarchy. It avoids copying files unnecessarily by comparing the file time-stamps and file sizes before transferring. (Perl) [GNU/Linux, Unix, Windows]
zsync: An implementation of rsync over HTTP.