Now if I got it wrong and it's not for browsing and just a soundtrack for Opera GX
I would definitely choose J.

I think you should name all of them and leave it to the user
I liked all of them but mostly the calm ones like G (for my mood rn) I think they are the best for browsing
Now this might not be the most common but it is my own opinion, and in case something loud and hardcore or like J for example won I'll have to turn it off when I'm not in the mood for it.
And that's the point sometimes we want something like A or J and sometimes G or E.
so leave it to the user.. Thank you