Schwanengesang ("Swan song"), is the title of a collection of songs written by Franz Schubert at the end of his life and published posthumously. Ständchen "Serenade" is the most popular and famous.
For Guitar quartet. Easy to early intermediate with some fingering suggestions.
With downloadable mp3 for audio help (one file with all guitars for play-along or practice the guitar).
Pages: 9 pages score and parts (4 pages full score (all guitars), 1 page Guitar1, 1 page Guitar2, 2 pages Guitar3, 1 page Guitar4). 4:10 min.

Ave Maria by Johann Friedrich Franz Burgmuller, generally known as Friedrich Burgmuller (4 December 1806 13 February 1874).

Guitar solo. Early Intermediate.
With downloadable mp3 just for audio help.

With standard notation and tablature (TAB).

Pages: Two (2) pages, 1:45 min.

Pasillo for Classical Guitar solo by  Emillo Murillo (1880-1942).

Guitar solo. Advanced Intermediate.

With standard notation and tablature (TAB).
With downloadable mp3 just for audio help.

Pages: Five (5) pages, 2:10' min.

Seven selected Opera themes for Guitar solo.
Romance de Nadir is extract of Act I 'Je crois entendre' (I Hear as in a Dream) from the opera 'Les pêcheurs de perles' (The Pearl Fishers), by the French composer Georges Bizet, first premiered on 30 September 1863. Easy to Early intermediate, 1:45'min. Two (2) pages.

Rinaldo is an opera by George Frideric Handel (1685-1759), composed in 1711, and was the first Italian language opera written specifically for the London stage. Here is an arrangement of the popular piece Lascia ch'io pianga (Almirena act 2) for Classical Guitar. Easy to Early Intermediate, 2:09' min. Three (3) pages.

Casta Diva (Norma - Cavatina) theme by Vincenzo Bellini (1801-1835). Intermediate Guitar, 36 bars. Two (2) pages.

Mattinata (morning), is a well-known work by Ruggero Leoncavallo (23 April 1857 – 9 August 1919, an Italian opera composer. Early Intermediate. 1:30 min. Two (2) pages.

O mio babbino caro ("Oh my dear daddy") is a soprano aria from the opera Gianni Schicchi by Giacomo Puccini. The aria was first performed on 14 December 1918 at the Metropolitan Opera in New York. Early Intermediate. 1:18 min. Two (2) pages.

O Sole Mio is a Neapolitan song written in 1898 by Eduardo di Capua (1865 -1917). O sole mio translates literally as "my sunshine". Easy to early Intermediate,1:20 min. Two (2) pages.
Habanera by  Georges Bizet from opera comique Carmen.

Guitar in drop D tuning (low E to D). Intermediate. 1:29 min.Two (2) pages.

With Tablature. With downloadable mp3 just for audio help.
Total: 15 pages.

Fifty selected National Airs of different Nations for Classical Guitar solo.

Around early intermediate to Intermediate level, while there are a few on easy and advanced intermediate level.
With downloadable mp3 just for audio help. With standard notation and tablature (TAB).

Pages: Fifty  (50) pages, 40' min.

1. March by Rossini,  2. Russian Air,  3. Andante by Beethoven,  4. The Last Rose of Summer,  5. French Air,  6. Un Noel an old French Air,  7. Le Petit Tambour,  8. Russian Air,  9. Polish National Air,  10. Scotch Air,  11. German Air,  12. Russian Hymn,  13. John Anderson,  14. Tyrolian Air,  15. Danish Air,  16. Cherubinis Air from Faniska, 17. Polish Hymn,  18. Kelvin Grove,  19. Podolian Air,  20. Fra Tante Angoscie,  21. Au Clair,  22. Dutch Air,  23. Portuguese Hymn,  24. Air by Gelinek,  25. Pyrenese Melody,  26. Polish Air,  27. Scotch Air,  28. Pleyels Hymn,  29. Donald a Scotch Air,  30. Sicilian Mariners Hymn,  31. Auld Lang Syne,  32. German Air,  33. Scots Wha Hae Wi Wallace Bled,  34. Vive Henri Quatre, 35. Air from the Ballet of Nina,  36. Danish Air,  37. Post Horn Waltz,  38. Old German Air,  39. Air from the Ballet of Alfred the Great,  40. Polish Air Krakoviak,  41. Scotch Air,  42. Swedish Air,  43. Danish Air,  44. Il Pleut, Il Pleut, Bergere,  45. Rule Britannia,  46. Cest LAmour a French Air,  47. Scotch Air,  48. An Alexis,  49. Je suis Lindor,  50. Chanson des Marseillois.