Barcarolle by F.Schubert for Flute and piano duet, 10 pages (7 pages flute and piano score, 3 pages flute solo) 2:25 min, with downloadable mp3 just for audio help.

Canon in D combines melodically, scales, chords and arpeggios, 4 pages. 4' min.
Early intermediate.

• With finger position suggestions.

• With downladable free mp3 for audio help.

Serenade by Franz Schubert (1797-1828) for easy piano. With downloadable mp3 for audio help, 2 pages.

Casta Diva (Norma - Cavatina) by Vincenzo Bellini classical piano solo sheet music.  
With downloadable mp3 for audio help.
Early intermediate, 36 bars, 2;50' min

Ludwig van Beethoven's Piano Sonata No. 8 in C minor, Op. 13, commonly known as Sonata Pathétique, was written in 1798 when the composer was 27 years old, and was published in 1799. It has remained one of his most celebrated compositions.
Here is an arrangement for Cello and Piano accompaniment for Adagio Cantabille (op.13-II).
With downloadable mp3 for audio help.  Eight pages (6 page Cello and Piano and 2 pages Cello), 3:56' min.