What have songs have idioms in them?

There is "Idioms" by Ron Brown. It is a teaching song that uses quite a few idioms.

"I'm Gonna Wash That Man Right Outa My Hair" has an idiom in it. Washing someone out of your hair means you are finished with them and want nothing else to do with them.

Lady Gaga uses a lot of idioms in her songs. Here are some:

Alejandro

Nothing to lose: It means being in a bad situation that cannot get any worse, and a person may feel they can attempt nearly anything.

Alienated

Shooting star: This is someone who is rapidly rising to fame.

Fancy Pants

Fancy pants: Someone who acts in a manner which others think is overly elaborate or pretentious.

Poker Face

Poker face: That is when someone's face has no expression nor sign of emotion. It is most commonly used in the context of playing Poker because you don't want others to read the cards you have from the look on your face.

Russian Roulette: This is a very dangerous game that nobody should ever play which uses a revolver which is loaded with just one bullet. The players put the gun to their head and pull the trigger. Eventually, an unlucky player may shoot themselves and most likely die. However, the term is used for any situations in which a person takes unnecessary risks and are at the mercy of chance.

Monster

Wolf in disguise: That is an evil or dangerous person who pretends to be nice or friendly. That comes from an old fable about a wolf dressed up as a sheep.

Red and Blue

Old school: That means traditional thinking or behavior. Depending on the context, it can be positive (efficient ideas that work) or negative (backwards, living in the past).

Starstruck

Star struck: Being totally in awe because of someone's celebrity status.

Wonderful

Talking in circles: To talk a lot and not really say anything of meaning.