I've posted this as a sort of guide for those who want to know where certain pieces belong to which.
Chapter 3 - Piano Sonata No. 14 (Moonlight Sonata) 3rd Movement.
Chapter 4 - Bagatelle in F minor.
Chapter 7 - Piano Sonata No. 8 in C minor Op. 13 "Pathetique" 2nd Movement.
Chapter 9 - Für Elise.
Chapter 9 - Rondò alla ungherese, quasi un capriccio Op. 129 "Rage Over a Lost Penny".
Chapter 10 - "Music to My Ears" by DJ PON-3.
Chapter 10 - Concert Etude #4 for solo cello by Bukinik.
Chapter 11 - Cello Sonata in A Op.69: Allegro, ma non tanto, 1st Movement.
Chapter 11 - "The Old Grey Mare" Variations in the style of Beethoven. Improvised by Richard Grayson.
Chapter 12- Salve Regina (Cello solo, arranged from the Gregorian Chant by Tomoyan).
Chapter 13 - Symphony No. 1, 1st Movement.
Chapter 13- Symphony No. 1, 4th Movement.
Chapter 13- Symphony No. 2, 1st Movement.
Chapter 13- Symphony No. 2, 2nd Movement.
Chapter 13 - Symphony No. 2, 4th Movement.
Chapter 15 - Piano Sonata No. 17 "Tempest," 3rd Movement.
Chapter 17 - Symphony No. 3, 1st Movement.
Chapter 17 - Symphony No. 3, 2nd Movement.
Chapter 17- Symphony No. 3, 3rd Movement.
Chapter 17 - Symphony No. 3, 4th Movement.
Chapter 18 - Piano Sonata No. 14 (Moonlight Sonata) 1st Movement.
Chapter 19 - String Quartet op. 135 (Lento assai, cantante e tranquillo).
Chapter 22 - Nocturne No. 20 in C# minor by Chopin.
Chapter 23 - Piano Concerto No. 4 in G Major, Op. 58.
Chapter 24- Symphony No. 4, 1st Movement.
Chapter 24 - Symphony No. 4, 2nd Movement.
Chapter 24 - Symphony No. 4, 4th Movement.
Chapter 25 - String Quartet No. 13 in B-Flat Major, Op. 130: II. Presto
Chapter 27- Beethoven - Rondo a Capriccio REMIX by TPRMX
Chapter 27 - String Quartet No. 14 in C# minor, Op131. Allegro (7th Movement)
Chapter 28 - Piano Sonata No. 29 "Hammerklavier," Op. 106: 5th Movement
Chapter 29 - The Spectacle (Razzle Dazzle) from season 5, episode 24.
Chapter 29 - Symphony No. 5 in C minor.
Chapter 32 - Piano Sonata No. 1, Ops 2. 2nd Movement (Adagio)
Chapter 33 - String Quartet no. 15 op. 132. 3rd Movement: Molto Adagio.
Chapter 35 - Nocturne in Eb Major. Op. 9 No. 2 by Chopin
Chapter 36 - String Quartet in B-flat major, Op. 130. 5th Movement: Cavatina
Chapter 37 - "The Swan," for violin and piano by Saint-Saens.
Chapter 38 - Symphony No. 6, 1st Movement
Chapter 38 - Symphony No. 6, 2nd Movement.
Chapter 38 - Symphony No. 6, 3/4/5 Movements.
Chapter 39 - Turkish March, from "The Ruins of Athens," arranged for solo piano.
Chapter 40 - Violin Sonata No. 9 (Kreutzer), 1st Movement.
Chapter 40 - "Mark Yonder Pomp of Costly Fashion," arranged by Beethoven.
Chapter 41 - Violin Concerto In A Minor, 1st Movement by Vivaldi.
Chapter 41 - Native American Music & Chants by Phil Thornton.
Chapter 41 - "Oyate Miye" (War Song) by The Native Tribes United.
Chapter 41 - "Lakota Lullaby" by Robert "Tree" Cody.
Chapter 41 - Auld Lang Syne by Beethoven.
Chapter 42 - Cello Sonata in D Major No. 5, Adagio.
Chapter 43 - Piano Trio No. 3 in C minor Op. 1 No. 3: IV. Finale (Prestissimo).
Chapter 44 - Violin Romance No 1, Op. 40.
Chapter 45- Egmont Overture.
Chapter 45 - Symphony No. 7: 1st Movement
Chapter 45 - Symphony No. 7: 2nd Movement.
Chapter 46 - String Quartet: Große Fuge, op. 133
Chapter 48 - Missa Solemnis: Kyrie (excerpt).
Chapter 48 - Missa Solemnis: Gloria in excelsis Deo
Chapter 48 - Missa Solemnis: Gloria; In gloria Dei Patris
Chapter 49 - Missa Solemnis: Credo; Et incarnatus est
Chapter 49 - Missa Solemnis: Credo; et vitam venturi sæculi
Chapter 49 - Missa Solemnis: Sanctus; Benedictus
Chapter 51 - Piano Concerto No.6 in B flat, K.238. 2nd Movement: Andante un poco adagio by Mozart.
Chapter 53 - Choral Fantasy for Piano, Orchestra and Choir.
Chapter 54 - Coriolan Overture
Chapter 54 - Symphony No. 8: 1st Movement.
Chapter 54 - Symphony No. 8: 2nd Movement.
Chapter 54- Symphony No. 8: 4th Movement.
Chapter 55 - In fourore iustissimae irae, RV 626. By Vivaldi.
Chapter 57 - Symphony No. 9: 1st Movement.
Chapter 57 - Symphony No. 9: 2nd Movement.
Chapter 57 - Symphony No. 9: 3rd Movement.
Chapter 57 - Symphony No. 9: 4th Movement (Ode to Joy).
Chapter 59 - Piano Concerto No. 1, 2nd Movement: Largo, Romance by Chopin.
Chapter 59 - Piano Concerto No. 5, "The Emperor"
Chapter 59 - Bagatelle No. 3. Op. 126.
Chapter 61 - Reconstructed Largo from Oboe Concerto in F Major (Hess 12)
Chapter 61 - Symphony No. 10, Unfinished (Reconstructed by Barry Cooper)
Chapter 61 - Beethoven's Last Thoughts (reconstruction from the sketches of Ludwig van Beethoven)