Mozart’s 12 Duets K.487 is an interesting collection for a few reasons. Mainly, there is quite a bit of controversy over what instrumentation the duets were actually written for. It was originally presumed to be a set of violin duos, then was later attributed to the basset horn. When the remaining autograph text was inspected by experts, they concluded that french horn may have been what was intended.
No matter what the original intention was, these duets have now been transcribed and arranged in every possible combination, and for good reason. They are a nice challenge, melodically interesting, and a pleasure to perform or sight read. In my mind these are essential to all trombone studios and every serious player.
You can dig into the first entire duet for free in the samples, then grab an immediate PDF download above.