Variety of styles? It was bad enough back in the pre-2010 era, before they changed the Kingdumb maladies. They threw a few off-notes in, a few extra lines in one song, and call that "variety"? And it has probably gotten even worse with that abomination of a new book. And that's what they are supposed to listen to, all the time.
Now, for variety, I listen to quite a few different styles. I have a MP3 player I use for work, and that contains something like 2,000 of my favorite songs. Therein lie pop rock from the 1960s, R&B from that era, hard rock and heavy metal (from the 1970s and '80s), disco, dance, funk, soul, and even some country music thrown in for good measure. It also includes some R&B and rap music from the 1990s, and pop music through. Including bubblegum music, psychedelic rock, garage rock, house and dance music (post-disco), and even the song Gathering Crowds (which was a real pain to find). I even have a few Christmas songs on that--I have a different MP3 player that has all Christmas songs, in a variety of styles, that I use for the Christmas season.
And that isn't "all inclusive". You can search that MP3 player all day and not find a single song from Barbra Streisand or Yanni. No Barry Manilow or Neil Diamond, either. Just real music. That is far more than can be said about only 150 songs or so (they keep changing the number, but it is all the same lousy styles) in their books.