I love that AnkiDroid allows you to assign buttons to actions. For instance, I have been using the volume buttons of my phone to choose Again and Good in review sessions. I enjoy this feature a lot.
Now, it would also be nice if the app would recognise media-playback buttons as buttons, such as those on earbuds or earphones: pause, previous/skip, volume up/down, etc.
I think this would be great. You could go through your reviews using just the three-button remote of your earbuds. Or even one of those wireless camera controllers – I believe they use media controls under the hood.