In my case I always like listening to “A whiter shade of pale”, it always works.
Dizzy Wright - Killem Wit Kindness
This song always helps me realize how being upset is really nothing more than a barrier to clear thought and working past differences. Great jam to boot too!
A Warm Place by Nine Inch Nails
Usually the entire soundtrack of the Ori series: Ori and the Blind Forest & Ori and the Will of the Wisps. In particular, my favorites to calm down is “Separated by the Storm” and “Ori, Embracing the Light”
Fade to black, Metallica usually.
Oh Wonder’s self titled Album. The first one is pretty relaxing.
On A Good Day by Oceanlab.
Don’t Stop Me Now by Queen. No matter how bad I feel, it always makes me feel better, and it’s lively enough that it inspires me to channel that energy into somehing more productive than just venting.
Necromancing Dancing by bear ghost can lift my mood regardless of why I’m upset. but it usually 'Depends on what I’m upset about. I try to find a song that is about the issue I’m experiencing. It helps me better articulate why I am upset I guess.
Might be a bit odd of an odd one, but the theme that plays on your ship from Star Wars: Knights of the Old Republic II: The Sith Lords is a song that never fails to help calm me down.