On OS/X, Command-~ switches between windows associated with the program with current focus. This is very handy when toggling through a set of browser windows or editor windows, for example. A couple years ago I noticed someone using similar functionality on a Gnome linux laptop and they showed me how to set it up, but I forgot the details (so I know it's possible).
I frequently switch between MacBook and a variety of linux systems running Gnome, Unity, and occasionally KDE. My Google-fu failed so I turn to stack exchange: How do I bind Alt-~ or similar key to give me functionality to switch between windows of program with current focus with linux windows managers?