Berlioz's
Symphonie Fantastique - "The Dream of the Witches Sabbath" section might have some good parts you could use
Orff's
Carmina Burana
Holst
The Planets - The "Uranus" section
Dukas - The Sorcerer's Apprentice
Prokofiev -
Romeo & Juliet No. 2 "Montagues and Capulets"
Grieg - From
Peer Gynt - In the Hall of the Mountain King
Mussorgsky - "Night on Bald Mountain"
Borodin -
Prince Igor, Polovtsian Dances
What kind of movie are you making?