Icons8 - Free app for Mac & Windows already containing 39,800 icons. Allows to search and import icons…
SVGMagic - It's a simple jQuery plugin that searchs for SVG images on your website and creates PNG versions on the run. Meaning that you don't have to create different versions of the images yourself.
Feather Icons - Simply beautiful open source icons
Flaticon - A database of free vector icons.
IcoMoon - IcoMoon is an icon management tool that is build to provide iconography.
Font Awesome - Font Awesome makes it easy to add vector icons and social logos to your website. And version 5 is redesigned and built from the ground up!