I enjoy
http://www.macjams.com, which is a long-running site for amateur musicians. It started with people using Macintoshes (hence the name). The front panel has a random song-picker which I routinely use for office music. (It's a very Forrest Gump experience: "you never know what you're gonna get.")
Most of the music is freely downloadable (for non-commercial use ... the contributors
want to share), and the variety of stuff is pretty much endless.
Many contributors are amateur, but a few of them are professionals. There's also a lot of collaboration ...
"hey, I need a vocal track to go with this!" or
"does anyone play the sitar?" (yes ...) or
"if I send you the tracks, can you remix this for me?" (yes, I should have some time on the console this week after the commercial projects are done). That sort of thing. All the time.
The most refreshing thing about the site, to me, is that people are contributing music because they
enjoy it (and generally are quite good at it), not because they harbor dreams of becoming the next
(ugh) Taylor Swift. Having said that, though, I have seen people report that a song which they'd contributed to
MJ, sometimes many years ago, got picked up
(licensed ...) for use in a movie.
When you listen to "commercial radio," you encounter an absolute
lack of variety. But when you listen to a site like this one, you're routinely astonished at the variety of music that can be and has been made.