An interesting one to look at might be Brahms' Piano Quartet No. 1, which was arranged for orchestra by Schoenberg. It is perhaps one of the best examples I can think of. Also, Ravel's Le Tombeau de Couperin, which was partially transcribed for orchestra from the original piano version by the composer. Also, some of Debussy's preludes were transcribed for orchestra by Colin Matthews, and some of his etudes were transcribed for orchestra by Michael Jarrell. The latter two examples are perhaps most interesting from an orchestral perspective, given how much orchestration techniques have changed over the years.