NexusFont - Choose and manage your fonts with Nexus Font.
Google Fonts - Making the web more beautiful, fast, and open through great typography
Font Manager - Simple font management for GTK+ desktop environments
FontJoy - Get smart font pairings in one click
FontExpert - FontExpert - Font Manager for Windows, Photo Manager for Digital Photography.
Better Google Font Finder - Sort & compare Google Fonts by their visual attributes.