List of Soundscapes
Here is a list of soundscapes. An easy way of testing them is to use the playsoundscape console command, which includes limited searching for soundscape names so you shouldn't have to print out a copy of this list for reference.
Soundscapes with 'util' in the name are intended for inclusion in other, full soundscapes. While they should work without problems in-game, they generally aren't nearly as varied or deep as the resulting composites. Others have positional sounds which will be played at certain locations specified in the env_soundscape entity's properties. If these locations are not given, the sounds will not be heard.