Music played on the Holiday episode of Quiet is the New Loud:

Carol of the Bells
The Bird and the Bee – Carol of the Bells – Single

Taxi (Ave Maria) (Jacknife Lee Remix)
Perri Alleyne – 28 Days Later OST

Away In a Manger
Bright Eyes – A Christmas Album

White Winter Hymnal
Birdy – Birdy (Deluxe Version)

Silver Bells (feat. School of Seven Bells)
The Polyphonic Spree – dream: Sounds of the Holidays, Vol. 1

Christmas Time Is Here
Au Revoir Simone – I’ll Stay ‘Til After Christmas

Winter Song
The Head And The Heart – The Head And The Heart

Northern Lights
St. Vincent – Strange Mercy

Have Yourself A Merry Little Christmas
She & Him – A Very She & Him Christmas

Did I Make You Cry On Christmas? (Well, You Deserved It!)
Sufjan Stevens – Songs for Christmas

Flowers in December
Mazzy Star – Among My Swan

And Anyway It’s Christmas
!!! – And Anyway It’s Christmas – Single

The Blizzard
Camera Obscura – The Blizzard – Single

North Pole Transmission
FC Kahuna – Machine Says Yes

A Holiday Song (Happy Holidays)
Starflyer 59 – The Fashion Focus

Last Christmas
Stardeath and White Dwarfs – Gift Wrapped, Vol. II: Snowed In

Winter Fields
Bat for Lashes – The Haunted Man (Deluxe Version)

Christmas Is Coming Soon
Blitzen Trapper – I’ll Stay ‘Til After Christmas

Reindeer
The Knife – The Knife