IconStore - Free icon packs by first-class designers
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Streamline icons - The world’s largest icon pack library - 100k icons and illustrations.
Sketch - Professional digital design for Mac.
Animated Icons from Icons8 - Massive collection of full-motion animated icons to make your project shine
Affinity Designer - Professional creative software, exclusively for Mac.