I'm not sure I know a song that is completely Taoist, but several have the leanings, and I do have my favorites.
"Let It Be" will always be a favorite, I loved it before I knew anything about Taoism, and it speaks volumes more to me now.
"Bare Necessities" I love the subtle minimalist messages in this song from The Jungle Book.
River" by Garth Brooks is another song that I have always loved. In
fact, I did my final lyrical dance number to this song back in the day.
couple of newer songs are by Plain White T's: "Rhythm of Love" &
"Welcome to Mystery" or Natasha Bedingfield's "Unwritten".