Flaticon - A database of free vector icons.
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!
Iconfinder - Iconfinder is the leading search engine and market place for vector icons in SVG, PNG, CSH and AI format..
IconArchive - Search through more than 735,000 free icons. Browse icons by category, artist, popularity, date. Organize and share your favorites.
Icons8 - Free app for Mac & Windows already containing 39,800 icons. Allows to search and import icons…
The Noun Project - Creating, Sharing and Celebrating the World's Visual Language