NexusFont - Choose and manage your fonts with Nexus Font.
Font Manager - Simple font management for GTK+ desktop environments
Fonty - Simple tool for testing web fonts directly on live sites
Connect Fonts Powered By Suitcase - A flexible font manager that uplevels the classic desktop application with intuitive search, pairing suggestions, and remote access in the cloud to keep you inspired, no matter where you are.
Font Viewer - Font Viewer is an application which does exactly that - it views fonts!
RightFont - The future of font manager software for Mac OS X