Google Fonts - Making the web more beautiful, fast, and open through great typography
FontJoy - Get smart font pairings in one click
Better Google Font Finder - Sort & compare Google Fonts by their visual attributes.
WhatFont - The easiest way to identify fonts on web pages
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!
What Font Is - Find any font from any image (commercial or free)