There are many sizes and tunings apart from the most popular ten hole diatonic. With the 1925 arrival of the Hohner Chromatic Model came the Bass Harmonica, Chord Harmonica plus the specialty Glissandro used for flashy fills. Virtuoso Harmonicist Tommy Morgan demonstrates most of them on this You Tube link.
As the need to be able to play different styles of music specialty tunings become available firstly through the enterprise of harp player Lee Oskar. Here’s some links of him playing these models in styles that suit the different tunings. [Read more]