You can get the three-button navigation bar back on Android by opening Settings and selecting 3-button Navigation under ...

Google may be testing the option to customize Android's navigation bar to add a little more than what's currently available.

How to set up an Action Button on Android with a mapping app Most features with customizable buttons on Android phones are part of the touchscreen. That's nice, but not exactly an Action Button.

Use QuickClick to add extra 'buttons' to your Android device The app tweaks your volume buttons for things like turning on the flashlight, sending messages, and running apps.

Google is preparing some new features for Android’s desktop windowing mode, including a button to minimize apps.