Sega have only revealed a handful of songs from Hatsune Miku Project Diva f, but the full game will include over 30 songs, all of which are new to the series, according to flyers distributed at a demo event. Furthermore, six of these songs have been created specifically for the game.
The flyer also mentions over 80 modules that you can outfit the Vocaloids with. These, too, are new. Hatsune Miku Project Diva f will be released on August 30th in Japan. You can view a rundown of all the songs that have been revealed for the game so far in this post.