App Icon Maker - Create icons for mobile app stores online for free.
EasyAppIcon - EasyAppIcon helps you to create your own app icons easily. Supporting Android Adaptive Icon!
MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
App Icon Generator - Generate icons and images for mobile apps, android and iOS. No need to upload or download. Works on your browser
favicon-generator.org - Generate icons for website and mobile app stores.
App Icon Resizer - A service to resize your app icon to all needed resolutions