Types of Trombones
As well as the Bb tenor trombone the broader trombone family is much larger than you might at first realise, with instruments of all sizes and some specialised for specific genres.

The Trombone section
Trombones and their players are known for their gregarious nature and are usually found in sections! In most bands this will take the form of two tenors and a bass trombone and in a jazz genre big band, three tenors and a bass. Sometimes, especially when accompanying choral music, an orchestral section will have an alto, a tenor and a bass and will spend most of the piece supporting the choir’s singers.
Of course, there are plenty of times when there is only one trombone player like in a jazz combo or rock/pop band horn section. Sometimes music theatre productions only have one trombone player and quite often this takes the form of a bass trombone player.
The trombone family
The B♭, tenor, slide trombone is by far the most popular trombone and the one most players begin learning how to play trombone on. Like all brass instruments however, the B♭ tenor trombone is part of a whole family of trombones ranging from the tiny sopranino trombone, which is a quarter the length of a B♭ tenor to the big contrabass trombone which is up to twice as long as the normal B♭ instrument. Some trombones use the piston valves (like the B♭ trumpet) and are called valve trombones and others have short, round rotary valves either instead of the hand slide or to augment the tube length options, but they all do the same job, adding tubing.