Используйте приложение APKPure
Историческую версию Smart App Swicher можно получить на Android
Простое приложение для быстрого переключения между другими приложениями.
A simple Application for fast switching between your favorite apps that you use frequently , similar to Omni Swipe (ex-Lazy Swipe) in switching between apps except that you choose the apps you want to favorite your self and it works as floating widget similar to facebook messenger chat head.
You can check the linked video to see how it works.