WinSpy - Retrieve window information.
KDocker - KDocker will help you dock any application into the system tray.
Microsoft Spy++ - Spy++ (SPYXX.EXE) is a Win32-based utility that gives you a graphical view of the system’s...
RBTray - Allows almost any program to be minimized to the system tray by right clicking its minimize button.
Winspector Spy - Have you ever used Spy++ that comes with MSVC?
stalonetray - Stalonetray is a stand-alone system tray (notification area) for X Window System/X11. Working with virtually any EWMH-compliant window manager, it has minimal build and run-time dependencies (X11 lib only). Complete XEMBED support under development.