App Icon Template - Royalty free app icon creator for iOS, OS X and Android
ASO Tools by AppFollow - Tools for App Store Optimization in App Store & Google Play
Radix Icons - A crisp set of 15×15 icons. Open source.
App Launch Checklist - Planning tool for launching your app successfully
Drawcon - Draw your own app icons
StorePreviewer - See how your app will look like on the App Store