Custom Android Virtual Device (AVD) skins.
Place the directory of the desired skin(s) in a rememberable location, such as a custom directory within the default Android Studio skins directory:
<Android Studio path>\plugins\android\lib\device-art-resources\custom-skins
Create/edit an AVD and click "Show Advanced Settings". Under "Custom skin definition", click the "..." button and select the folder containing the skin you want to use.