If you keep more than a hundred fonts in your System Folder, you need a font utility. TypeTamer helps manage long font menus, but since its initial release, it has lost its relevance in a world of more full-featured tools.
The latest version, TypeTamer 2, lets you group and view fonts in easily negotiated sets, and shows WYSIWYG previews of fonts in different sizes. It also identifies TrueType and PostScript fonts.
But these days, tools such as Diamondsoft's Font Reserve 2.5 can activate and deactivate sets of fonts: a much better way to manage them. Also, TypeTamer is not compatible with Adobe InDesign and other software, and it behaved inconsistently in QuarkXPress.