Google Fonts - Making the web more beautiful, fast, and open through great typography
WhatFont - The easiest way to identify fonts on web pages
FontJoy - Get smart font pairings in one click
Font Flame - Tinder for font pairing
Better Google Font Finder - Sort & compare Google Fonts by their visual attributes.
Pair Compare - Pair & Compare is a web application that lets you try, pair, and compare different fonts easily and quickly. Pair & Compare allows you to use hundreds of Google Fonts, or one of the fonts installed on your device.