A recent question on tuning saxophones caused me to wonder on the variety of transposing instruments. Here's some that I already know:
C - Non-transposing or by whole octaves.
At concert pitch - too many to mention.
Octave above - piccolo.
Octave below - double bass and double bassoon. Also guitar and bass guitar.
Some piccolos. So, an octave and minor second above?
It is not the most common but there is trumpet in D.
E♭ clarinet - minor 3rd above.
Alto sax - major 6th below.
Baritone sax - octave and major 6th below.
French horn and cor anglais - Fifth below
I have a tin whistle labeled G but, as explained in A♭, this could be regarded as transposing in F. A fourth above.
I have a tin whistle which is labeled B♭ but this refers to its lowest note which is D on a standard whistle. So, if treated as a transposing version of the common D whistle, it would be a major 3rd below and hence in A♭.
A clarinet and oboe d'amour - minor 3rd below
Many. This seems to be the most common case.
Trumpet, B♭ clarinet, soprano sax - a major second below.
Bass clarinet and tenor sax - Octave and a major second below.
What others am I missing? I have said little on brass instruments as I don't know them well enough to be confident that I was right. E.g. Wikipedia says of the tenor trombone: "is a non-transposing instrument pitched in B♭". So, where do I enter that?