xtctl is a script for setting/changing xterm properties. It can change the foreground, background, cursor, and mouse colours of an XTerm window, and the icon and background image (only known to work with Eterm). xtctl can also modify the window's title, icon name, highlight background, font, size, position, z-order (raise and lower), and iconified/restored status. There are experimental options for full and soft reset.
yEd is a powerful diagram editor which can be used to quickly create diagrams manually or import external data for analysis and auto-magically arrange even large data sets by just pressing a button. You can use yEd to quickly create flow charts, BPMN and UML diagrams, organization charts, mind maps, Entity Relationship diagrams, and many other kinds of diagrams, graphs, and networks. Choose from a wide range of highly sophisticated layout algorithms to automatically arrange diagrams in no time. An intuitive and visually appealing user interface makes creating diagrams fun. Once a diagram has been created, it's easy to save, print, or export it to popular formats like PDF, SWF, EMF, SVG, JPEG, GIF, PNG, or HTML image maps.
yeahwm (yet another h* window manager) is a minimalist window manager based on evilwm. It supports Xinerama and respects aspect size hints (useful with Mplayer and tvtime). It features creative usage of the mouse, tabbed titles that can be repositioned (BeOS-like), and good keyboard control.
zLogFabric is an all in one cross-platform logging solution that collects log lines/messages over a messaging system to a central server instance. The modular design enables the server to store, forward, alert, and generate live statistics out of the logged data. It can collect log information from files, syslog, log4j, log4net, and Windows event logs.
zap is a Perl wrapper for rm, meant be to used by the root account. It checks the list of files passed as arguments against a configuration file to make sure that root doesn't accidentally delete a protected file/directory. The root account(s) should make this script an alias for rm in their .bashrc file.