emojione - The finest emoji you can use legally
MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
Emojination - A simple design tool combining emojis and modern aesthetics.
EasyAppIcon - EasyAppIcon helps you to create your own app icons easily. Supporting Android Adaptive Icon!
App Icon Template - Royalty free app icon creator for iOS, OS X and Android
App Icon Maker - Create icons for mobile app stores online for free.