Sonata - [Win - Mac] Description and order form for this font by Adobe. - http://store.adobe.com/type/browser/P/P_021.html
Toccata and Fughetta - Two fonts designed to be used with Finale. Includes samples, free demos, and ordering information. - http://www.efn.org/~bch/AboutFonts.html
FacSimilus - Sibelius and Finale fonts including figured bass, common and special symbols, ornaments, special and straight lines. - http://www.facsimilus.com/FacsimilusFontFamily/en/Default.aspx
Express Music: Fonts - Offers three music fonts: Ashmusic, Leemusic and Russmusic. Available for both Mac and PC. - http://expressmusic.com/
Caltabiano: Music Fonts - Offers Sicilian Numerals, Ghent Percussion Font, and Rehearsal Letters. Samples and order form available. - http://www.caltabiano.net/shareware/index.html
Bach, Musicological Font - [Win - Mac] Shareware font for writing essays or compiling databases which need to have some musical symbols in them. - http://www.music.qub.ac.uk/~tomita/bach-mf.html
November - Made up of more than 330 symbols, from basic shapes such as note heads, clefs and rests, up to rarer characters like microtonal accidents, plain-song clefs or baroque ornaments. - http://www.klemm-music.de/november/index_e.htm
Gregorian Chant Fonts - Featuring StMeinrad and StMeinradAux, that contain the symbols necessary to reproduce Gregorian chant. - http://www.music.princeton.edu/chant_html/fonts.html
DVM Publications - Company that features some font packages for engravers and publishers: includes demos and online ordering. - http://www.dvmpublications.com/
Sigler Music Fonts - Features Jazz Font and Swing Font, usable with Finale and Overture. Includes demo pages, online ordering form. - http://www.jazzfont.com/