IconStore - Free icon packs by first-class designers
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Streamline icons - The world’s largest icon pack library - 100k icons and illustrations.
Invision - Prototyping and collaboration for design teams
Animated Icons from Icons8 - Massive collection of full-motion animated icons to make your project shine
Sketch - Professional digital design for Mac.