In the Fellowship of the Ring musical score, there are many themes that play. Most of them feature only in a single track, but some, like the central theme, play in several places, often with different variations. Here are a list of the themes that play in more than one place:
More themes...

1. The central theme. This plays in track:
   • 02, 0:05 - 'Concerning Hobbits'
   • 04, 1:25 - 'The Treason of Isengard'
   • 05, 1:28 - 'At the Sign Of The Prancing Pony'
   • 09 - 'Many Meetings'
     • 0:41
     • 2:27
   • 10, 2:25 - 'The Council of Elrond'
   • 11 - 'The Ring Goes South'
     • 0:25
     • 0:50
   • 13 - 'The Bridge Of Khazad Dum'
     • 0:00
     • 3:37
   • 15, 0:00 - 'The Great River'
   • 16, 4:28 - 'Amon Hen'
   • 17 'The Breaking Of The Fellowship'
     • 0:00-0:50
     • 1:43-5:18
     • 5:19-7:02 - 'In Dreams' (Vocal variation on theme)
     • 7:04
   • 18 'May It Be'
     • 0:00-3:26 (vocal variation)
     • 3:28

2. The Black rider theme. This plays in:
   • 'The Black Rider' [Track 5, 0:53]
   • 'A Knife In The Dark' [Track 7]
   • 'A Flight to the Ford' [Track 8, 2:31]

3. The Orc theme. This plays in:
   • 'A Knife in the Dark' [Track 7, 1:45]
   • 'Amon Hen' [Track 16, 2:10]

4. Gollum's theme:
   • 'A Journey In The Dark' [Track 12, 1:21]

Here are more themes that play

1. The Bree theme. This plays in:
   • 'At the Sign Of The Prancing Pony' [Track 6]

2. The Travelling theme. This plays in:
   • 'At the Sign of the Prancing Pony' [Track 6, 2:48]

3. The Moth theme. This plays in:
   • 'A Knife in the Dark' [Track 7, 2:15]

4. Arwen's theme. This plays in:
   • 'A Flight to the Ford' [Track 8, 0:00 and 2:32]

5. Rivendell theme. This plays in:
   • 'Many Meetings' [Track 9]

6. Aragorn/Arwen theme:
   • 'The Council of Elrond' [Track 10]

7. Lothlorien:
   • 'Lothlorien' [Track 14]