Android™ has quite a few built-in drawables available for us to use in our applications. The problem is that there are A LOT of them and they change from version to version. This site attempts to help you find the images you're looking for and see how they've changed over time.
From public to private drawbles, icons to dialogs, window trim to fades, every built-in drawable AOSP has given us is here (in mdpi-format).
Included are the drawables for all of the Android™ versions that Google™ still considers to be in use: