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!
AMP Font Viewer - Jump to Download - Download.
The Noun Project - Creating, Sharing and Celebrating the World's Visual Language
Font Manager - Simple font management for GTK+ desktop environments
Nucleo - Commercial vector icons and accompanying apps to manage and customize them.
What Font Is - Find any font from any image (commercial or free)