I feel you. My strategy of late has been to listen to a playlist of a genre I like but composed of artists I haven’t heard of on Spotify. I do this in the background while I am working. I heart the ones I like and add them to a special playlist and over time I’ve built up a few different playlists and expanded my inventory of tunes. Before being a programmer I was a studio musician and engineer and I swear I listen to more music now than ever.

Edit: incidentally, I totally agree with you about wishing there was a service that focused on mood/tempo more than anything. I’ve found that Spotify has been doing some of this type of aggregating and it’s not too bad. I’ve gotten a ton of good music from the Late Night Vibes playlist.