MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
App Icon Template - Royalty free app icon creator for iOS, OS X and Android
App Icon Resizer - A service to resize your app icon to all needed resolutions
Radix Icons - A crisp set of 15×15 icons. Open source.
App Icon Generator - Generate icons and images for mobile apps, android and iOS. No need to upload or download. Works on your browser
Drawcon - Draw your own app icons