The top official skills under this category are for Ambient Sounds, which provide Alexa with the capability of playing rain, thunderstorm, and ocean sounds, which can help users relax and sleep better. However, Alexa can also be linked to your Spotify account, if you have one, and can double as an excellent music player.
To learn more about Spotify and Alexa integration, navigate to https://www.spotify.com/us/amazonalexa/.
Hence, Spotify with Alexa is one of the top contenders in this category.