We violinists can consider ourselves very lucky in this respect, but pieces by the great piano composers would have been nice. Chopin and Rachmaninoff wrote cello sonatas, but nothing for the violin.
Likewise, we are blessed with five wonderful Mozart concertos, but I wish he had written one more later in his life. It seems a bit unfair that the pianists got 27 concertos. Maybe it would just be nice if it existed.