Daniel Wolf, of Renewable Music and Winter Album fame, has compiled a new survey of present-day composers who have written music for the melodica (or multiples thereof). Composers include Jon Brenner, Stephen Chase, Kieran Daly, Paul A. Epstein, Graham Flett, Aaron Hynds, Jukka-Pekka Kervinen, Kondo Kohei, Nomura Makoto, and Ushijima Akiko. There may be some new additions over the next few days.
My own piece, Redundens 1m, continues the ever-growing series of Redundens pieces. A mirror of the PDF will be added to the page shortly, and maybe an mp3 of a MIDI realisation (although good melodica soundfonts are hard to find). In the meantime enjoy the collection.