Fontmatrix

A font manager for Linux.

Fontmatrix is aimed at adventurous graphic designers and typesetters who need to manage hundreds and even thousands of fonts for their work - avoiding the need to browse overly long lists in dialogs.

Basically, Fontmatrix helps you do three things:

Activating and deactivating your fonts
Tagging fonts with sets
Finding suitable fonts by constructing simple or complex queries
Refining the fonts selection by comparing glyphs in details
Generating font "books" as PDF.

Find more at fontmatrix.net or from built-in help system.