In addition to works that were published during his lifetime, Wagner's
  output included sketches and drafts for stage works that were never
  completed. His first attempt at writing opera, at the age of 17, was
  soon abandoned and neither text nor music from his "pastoral opera",
  based on a play by Goethe, 'Die Laune des Verliebten', has survived. 
  His next operatic project was 'Die Hochzeit', WWV 31, from which three
  numbers have survived, although he destroyed the libretto. 

  Shortly after completing 'Das Liebesverbot' (see above), he attempted to
  write a grand historical opera, 'Die hohe Braut oder Bianca und
  Giuseppe', WWV 40. He completed only the libretto, which among other
  influences showed that of Schiller and which he allowed his friend Jan
  Bedrich Kittl to set to music. Kittl took such liberties with the book,
  however, in particular diluting the revolutionary content of the work
  and making much of the plot confused and unmotivated, that Wagner asked
  that his name be removed from it. The libretto that appears in volume 11
  of Wagner's collected works is the one rewritten by Kittl; it is unclear
  how much of Wagner's text remains in it, although a comparison with his
  prose draft shows that Kittl made significant changes. At about the same
  time, Wagner drafted a comedy based on a tale from the Arabian Nights:
  'Die glückliche Bärenfamilie', WWV 49. Unfortunately he abandoned the
  project after sketching the first three numbers.

  Later unrealised opera projects included 'The Mines at Falun' (Die
  Bergwerke zu Falun) WWV 67, 'Friedrich Barbarossa' WWV 76, 'Wayland the
  Smith' (Wieland der Schmied) WWV 82 and 'The Victors' (Die Sieger) WWV
  89. Only for the last of these did Wagner sketch any music; see Osthoff,
  1983.