Richard I. Schwatz has published on the web a catalog of more than 1000 solos for cornet -- with accompaniments for orchestra, or for band, or for piano -- beginning with 14 solos by the instrument's greatest master: Jean-Baptiste Arban.
file:///D:/SCANNED%20MUSIC%20A-L/~DOCS/Solos%20for%20the%20Cornet%20A-K.htm
file:///D:/SCANNED%20MUSIC%20A-L/~DOCS/Solos%20for%20the%20Cornet%20L-Z.htm
Most of these works were published in the US in the 19th Century. Cornet solos were enormously popular in the US, France and Germany at the time. Performers attained astounding levels of virtuosity. The works themselves were often musically sophisticated and melodically memorable.
And yet, today, this remarkable repertoire is virtually unknown and unperformed. This is a consequence, I think, of inaccessability to the printed music for cornettists, orchestras, bands and piano accompanists. Even on IMSLP, this genre is represented by only a few dozen examples (especially if one excludes chamber ensembles that incorporate the cornet.)
In order for the pieces with orchestral or band accompaniment to make a comeback into the current repertoire, it would be necessary to find and scan the full scores and/or the instrumental parts.
But where are these works to be found?
MS