If you want to wake up to your favorite music from YouTube Music, then Google Clock will let you do just that. For US users, the feature also comes to Pandora. Last year, Spotify was the first streaming service to support this feature.
To use your streaming service of choice, you just need to head to the alarm section and tap on the sound option beneath any given alarm. Each music service gets its own tab. You can select from a popular playlist or select from Spotify's library of playlists.
Source: The Verge