App Switch!

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.

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

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.