Mission Control is described as ', formerly Exposé, is a feature of the OS X operating system' and is an app in the OS & Utilities category. There are more than 25 alternatives to Mission Control for a variety of platforms, including Mac, Windows, Linux, BSD and Xfce. The best alternative is Dexpot. It's not free, so if you're looking for a free alternative, you could try KWin or Nimi Visuals. Other great apps like Mission Control are Witch (Paid), Contexts (Paid), Command-Tab Plus (Paid) and TotalSpaces (Paid).
Skippy-XD is a full-screen task-switcher for X11. You know that thing Mac OS X, Compiz and KWin do where you press a hotkey and suddenly you see miniature versions of all your windows at once? Skippy-XD does just that.
Activate wanted windows and apps with Tabber Window Switcher which is a Command+Tab alternative to switch windows. See contents of windows Real-Time when switching windows. Switch Apps and Windows with a shortcut or set a custom shortcut to switch windows or to switch apps.