Treble Clef Instruments also come with a duet harmony part.
When played with someone else it sounds like this:
CLARINET DUET
Bass Instruments come with the Melody Part and a Bass part.
When a Melody, a Harmony, and a Bass Part are combined it sounds like this:
WOODWIND TRIO
Percussion parts come with the melody for mallet percussion and a traditional percussion part that can be used by the drum section or played on the drum set.
BELLS & PERCUSSION
When all the parts are combined it sounds like a full band.