Use the original phone tracking app to find your phone. You can have Alexa make your phone ring on full volume or track it with the phones GPS.
Setup: First you'll need to download the Where's My Droid app on your phone from Google Play. Run the app and setup a Commander account. You'll then log into that Commander account through the Alexa app to link your account.
“Alexa, ask Where's My Droid to make my phone ring.”