I know you're not worried about copyright at this point, but this list is fantastic, and many of sites are searchable by the feel, tempo, genre, etc. Plus in the future if you do ever publish you'll be familiar with the sites.
It does take some clicking around to find the right thing, but that's half the fun.
http://fstoppers.com/bookmark-the-best-free-and-pay-music-websites-for-video-editors