Here is a list of soundscapes for use in Counter-Strike: Source. 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.
Aztec
| Name
 | 
Description and Notes
 | 
aztec.outdoors_e3
 | 
Continual noise of heavy rain and Crickets, Loud thunderclaps, calling birds and other jungle animal noises.
 | 
aztec.outdoors
 | 
Very similar to aztec.outdoors_e3 but slightly quieter and with the faint drone of an engine or generator.
 | 
aztec.indoors
 | 
Continual noise of Rain and Crickets, low howl of wind, occasional rumbles of thunder, falling drops and a steady electrical hum.
 | 
aztec.indoors_river
 | 
The similar to aztec.indoors but with churning water and without the electrical hum.
 | 
aztec.outdoors_river
 | 
Similar to aztec.outdoors with additional churning water, creaking timbers and a steady electrical hum.
 | 
Cobble
| Name
 | 
Description and Notes
 | 
cbble.indoors
 | 
A low rumble of wind / white noise with the occasional sound of shifting earth / shale.
 | 
cbble.under
 | 
A slightly louder rumble of wind / white noise with occasional sounds of shifting earth / shale, birdsong, knocks, creaks and distant planes overhead.
 | 
cbble.outdoors1
 | 
A loud rumble of wind / white noise with occasional sounds of shifting earth / shale, birdsong, knocks, creaks, distant planes overhead and a moo'ing cow.
 | 
cbble.outdoors2
 | 
Very similar to cbble.outdoors1 with a loud rumble of wind / white noise with occasional sounds of shifting earth / shale, birdsong, knocks, creaks and distant planes overhead.
 | 
Chateau
| Name
 | 
Description and Notes
 | 
chateau.indoor
 | 
Continual white noise with occasionl creaks.
 | 
chateau.outdoor
 | 
Continual white noise with a distant piano and the occasional sounds of shifting earth / shale, birdsong and distant planes overhead.
 | 
chateau.water
 | 
Continual white noise with churning water, occasional sounds of shifting earth / shale, a metallic clang, birdsong and distant planes overhead.
 | 
chateau.water_enc
 | 
A higher pitch white noise with churning water, occasional sounds of water drops and shifting earth / shale.
 | 
Compound
| Name
 | 
Description and Notes
 | 
compound.outdoora
 | 
No white noise, occasional howls of wind, planes overhead, passing vehicles, rattles amd clangs.
 | 
compound.indoora**
 | 
Low white noise, steady electrical hum, occasional sounds of gas inside machinery.
 | 
 | 
** When played using the playsoundscape command there is the continual buzzing of flies, in the level the flies are not present.
 | 
Dust
| Name
 | 
Description and Notes
 | 
dust.Indoors
 | 
Continual echoing wind, Occasional sounds of shifting earth / shale, creaks and distant helicopter rotor chop.
 | 
dust.Outdoors1
 | 
Continual rush of wind and stringed instruments playing. Occasional sounds of shifting earth / shale, creaks, distant helicopter rotor chop and a radio tuning in followed by some speech then tuning back out again.
 When played using the playsoundscape command the Stinged instruments are a large feature, in game, the volume of them varies according where in the soundscape you are.
 
 | 
dust.Outdoors2
 | 
Continual rush of wind and Drums playing. Occasional sounds of shifting earth / shale, creaks and distant helicopter rotor chop.
 When played using the playsoundscape command the drums are a large feature, in game, the volume of them varies according where in the soundscape you are.
 
 | 
Dust 2
| Name
 | 
Description and Notes
 | 
dust2.indoors
 | 
 | 
dust2.outdoors
 | 
 | 
Havana
| Name
 | 
Description and Notes
 | 
havana.indoors
 | 
 | 
havana.outdoors
 | 
 | 
Inferno
| Name
 | 
Description and Notes
 | 
inferno.Outside
 | 
 | 
inferno.Inside
 | 
 | 
inferno.LightbulbHum
 | 
 | 
inferno.RefrigeratorHum
 | 
 | 
inferno.CeilingFan
 | 
 | 
inferno.AngryDog
 | 
 | 
inferno.Cricket
 | 
 | 
inferno.Pigeons
 | 
 | 
inferno.TSpawn
 | 
 | 
inferno.Birds
 | 
 | 
inferno.FarBackCorner
 | 
 | 
inferno.BackAlley
 | 
 | 
inferno.TSpawnHall
 | 
 | 
inferno.BellTowerArea
 | 
 | 
inferno.LowerApartment
 | 
 | 
inferno.UpperApartment
 | 
 | 
inferno.BridgeApartment
 | 
 | 
inferno.BackHall
 | 
 | 
inferno.BalconyAlley
 | 
 | 
inferno.ApartmentHalls
 | 
 | 
inferno.SniperBalcony
 | 
 | 
inferno.BackBalcony
 | 
 | 
inferno.MiddleAlley
 | 
 | 
inferno.CrawlAlley
 | 
 | 
inferno.CrawlTunnel
 | 
 | 
inferno.BombsiteB
 | 
 | 
inferno.CTApartment
 | 
 | 
inferno.BombsiteBTunnel
 | 
 | 
inferno.DogBarkingInside
 | 
 | 
inferno.CTTunnel
 | 
 | 
inferno.CTSpawn
 | 
 | 
inferno.TheRuins
 | 
 | 
inferno.BombsiteA
 | 
 | 
inferno.ColumnAlley
 | 
 | 
Italy
| Name
 | 
Description and Notes
 | 
italy.indoor
 | 
 | 
italy.indoor_b
 | 
 | 
italy.indoor_t
 | 
 | 
italy.outdoors
 | 
 | 
Office
| Name
 | 
Description and Notes
 | 
office.outdoorsa
 | 
 | 
office.garagea
 | 
 | 
office.indoorsa
 | 
 | 
Piranesi
| Name
 | 
Description and Notes
 | 
piranesi.indoor
 | 
 | 
piranesi.outdoor
 | 
 | 
Port
| Name
 | 
Description and Notes
 | 
port.Outside
 | 
 | 
port.LightHum
 | 
 | 
port.LightHum2
 | 
 | 
port.MetalStress
 | 
 | 
port.TSpawn
 | 
 | 
port.TankFarmRoad
 | 
 | 
port.TankFarm
 | 
 | 
port.Pier
 | 
 | 
port.AroundTheWarehouse
 | 
 | 
port.Warehouse
 | 
 | 
port.TunnelTone
 | 
 | 
port.WarehouseTunnel
 | 
 | 
port.TunnelA3
 | 
 | 
port.TunnelA2
 | 
 | 
port.TunnelA1
 | 
 | 
port.Docks
 | 
 | 
port.Ship
 | 
 | 
Prodigy
| Name
 | 
Description and Notes
 | 
prodigy.computers
 | 
 | 
prodigy.vents
 | 
 | 
prodigy.tunnels
 | 
 | 
prodigy.hangar
 | 
 | 
Tides
| Name
 | 
Description and Notes
 | 
tides.tunnel
 | 
 | 
tides.courtyard
 | 
 | 
Train
| Name
 | 
Description and Notes
 | 
train.Outside
 | 
 | 
train.Dumpster
 | 
 | 
train.Traffic
 | 
 | 
train.Tank1
 | 
 | 
train.Tank2
 | 
 | 
train.BombTarget
 | 
 | 
train.Birds
 | 
 | 
train.TSpawn
 | 
 | 
train.TWalkway
 | 
 | 
train.BackAlley
 | 
 | 
train.BackCorner
 | 
 | 
train.SideAlley
 | 
 | 
train.CourtyardA
 | 
 | 
train.BombsiteA
 | 
 | 
train.CTSpawn
 | 
 | 
train.BombsiteBCatwalk
 | 
 | 
train.catwalk
 | 
 | 
train.BombsiteB
 | 
 | 
train.BackHall
 | 
 | 
train.BrickRoom
 | 
 | 
train.Restroom
 | 
 | 
train.LockerRoom
 | 
 | 
train.BreakRoom
 | 
 | 
train.SniperNest
 | 
 | 
train.Middle
 | 
 |