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!
Nucleo - Commercial vector icons and accompanying apps to manage and customize them.
IconArchive - Search through more than 735,000 free icons. Browse icons by category, artist, popularity, date. Organize and share your favorites.
IcoMoon - IcoMoon is an icon management tool that is build to provide iconography.
Iconfinder - Iconfinder is the leading search engine and market place for vector icons in SVG, PNG, CSH and AI format..