FontFace ninja - A browser extension to identify and try fonts on any website
AMP Font Viewer - Jump to Download - Download.
What Font Is - Find any font from any image (commercial or free)
Font Viewer - Font Viewer is an application which does exactly that - it views fonts!
Fontsnatcher - Fontsnatcher helps you in identifying, testing and discovering new fonts and typefaces being used on the internet.
Google Fonts - Making the web more beautiful, fast, and open through great typography