Witch!

VistaSwitcher is an elegant and powerful task management utility for Windows OS. Once installed, it replaces the default Windows Alt-Tab dialog with a nice box that shows a list of all running tasks, with their names and preview snapshots, and enables the user to take actions on them using the mouse and keyboard shortcuts. With just one click, you can switch tasks, minimize, maximize, restore the main window, or close the process.

HyperSwitch provides a compelling alternative to HyperDock for keyboard junkies.What's NewVersion 0.2.365-dev:

Command-Tab Plus Is a Powerful and Customizable macOS App’s and Windows SwitcherCommand-Tab Plus is designed to help you switch between apps and windows in a faster and more convenient way. A great alternative for Mac App’s switcher.

Have you seen the cool and nice effects of Windows Aero in Windows Vista? One of those effects is a view of your open windows in a three-dimensional stack on your desktop, and using hot keys, you can flip through the open windows to quickly locate and select the window you want. But wait a minute, don't you have Windows Vista? No problem, with Shock Aero 3D you can enjoy the same three-dimensional effect running on Windows XP desktop.

SmartTab, the better Alt-Tab (a Windows Alt-Tab Dialog replacement).

WinFlip emulates Windows Vistas "Flip 3D" effect for Windows XP. Using the hotkey of your choice, you can find the window youre looking for in a fast, clean 3D interface.

The ultimate desktop organizer. DeskPose NXT helps you to find your applications fast, organize your desktop and become more productive.

Manico is a fast application switcher for Mac that lets you access apps by simply holding the Option key and pressing the target number.

TopDesk radically reduces the time you spend switching between tasks by giving you the ability to quickly find the window you want from a thumbnail view.

If you are not familiar with the Alt-Tab task switcher in Windows, its a keyboard short-cut (hot-key) to enable fast switching between applications/windows. This feature has been in Windows since Windows 3.0 and is largely unchanged since Windows 95! Alt-Tab Thingy is a replacement to add brand new features to help you switch tasks faster and more efficiently than ever before!

LiteSwitch X follows the tradition of LiteSwitch as a simple solution for managing open applications using the keyboard. Like its predecessor which will continue to be available, LiteSwitch X has a clean, simple and functional style that has become Proteron's hallmark. It features an aquified transparent, resizeable window which is invoked by a configurable key-combination (default is Apple-Tab). From the pop-up window the user can switch to any application, hide, quit, or force quit any application or drag-and-drop files onto any application. Windows users migrating to the Mac can feel more at home having the Alt-tab functionality returned to them, yet enjoy it in its full Mac OS X splendor. »

With SpaceLauncher for macOS, you can launch or switch to an app by pressing a pre-defined key while holding down spacebar.