Some of the music stuff I want to mention. These are suitable mainly for producers and djs not for real songwriters perhaps. But in a case you miss a drummer and a bass player there are quite a bunch of real recorded material for sale. Also with a high quality. There are very much free loop/sample websites offering free loops which often are low quality and garbage. I must say this bluntly but most free sample websites are full crap.
I have only bookmarked very few which are worth mentioning and here´s couple of them: Platinumloops and Zenhiser. These websites have got some high quality loops and samples which are suitable for almost any music production. The Zenhiser samples are better suitable for dj and dance producer I think. In Platinumloops there´s vast range or samples from Hip Hop, Jazz, Drum and Bass to Rock and Metal to choose from.
Check out the free samples at Platinumloops here
Zenhiser sample website here