http://tapestry.allmusic.com/
Here you can hear a collection of songs (30 seconds each, unfortunately) of any style (Avant-Garde), theme (Scary music), and tone (Hypnotic).
Here's an abbreviated version of a list of songs that supposedly fit into the Avant-Garde/Scary music/Hypnotic category:
KEEP YOUR DREAMS - Suicide
ANCIENT DELAY - Wolf Eyes
SAETA - Nico
HER EYES WERE HUGE THINGS - His Name is Alive
IT'S A RAINY DAY... - Faust
IT'S MORE FUN TO COMPUTE - Kraftwerk
GOLDEN HOURS - Brian Eno
ANTARCTIC RETURN - Bjork
SEXTET - Steve Reich
SATAN IS BORING - Sonic Youth