Android Design
Material Design → Icons
… delightful, beautifully crafted symbols for common actions and items. Download on desktop to use them in your digital products for Android, iOS, and web.
App Icon Sizes · phonegap/phonegap Wiki · GitHub
access core functions on Android, iPhone and Blackberry using JavaScript - phonegap/phonegap
Simple Android Icon Size Guide for Lollipop 5.1
App Icon Template
… a free Photoshop resource that makes it easier for you to make icons. Edit a single object and it’ll automatically render out all the various sizes required on iOS & Android. Build in textures and colors make it easy to get started and the bundled actions make exporting a breeze.