IconStore - Free icon packs by first-class designers
iOS 11 icons: Glyphs - Most demanded iOS 11 icons for free by Icons8
Streamline icons - The world’s largest icon pack library - 100k icons and illustrations.
Iconjar - Store all your icons in one place, just a click away
MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
Feather Icons - Simply beautiful open source icons