Icons
Font Awesome 4
Font Awesome gives you scalable vector icons that can instantly be customized — size, color, drop shadow, and anything that can be done with the power of CSS.
Themify Icons
Themify Icons is a complete set of icons for use in web design and apps, consisting of 320+ pixel-perfect, hand-crafted icons that draw inspiration from Apple iOS 7 - available to the public, 100% FREE! You may use or distribute it for any purpose, whether personal or commercial. This icon set is a must have tool for web designers and developers.
Material Design Icons
Material Design Icons' growing icon collection allows designers and developers targeting various platforms to download icons in the format, color and size they need for any project.