My Music Source, Digital Juice, Footage Firm, Sounddogs, SoundRangers, Audio Jungle, RoyaltyFreeMusic.com, Pond5 and a few more that I am sure I am forgetting. If there are some other good ones that you use, please let me know! The good news is that there are tons of options. When I first started working in radio/tv, at most stations we would generally have one CD library of anywhere from 10-30 discs. And because most of those discs were specialized and rarely useful (eg. Caribbean, Techno, Punk, Metal, Groovy, etc.), you pulled most cuts from about 3 or 4 discs (eg. Corporate, Motivational, Reflective, Up Tempo, etc.). That was it. Producing several spots a day sometimes, the same songs got used over and over and over. That is not a problem anymore. There is plenty to choose from, it just takes a little time to track it down.