On Tracklib, you can sample not only 1000s of songs not available anywhere else, but also get access the original studio stems. 

We also create separated stems for songs so that you do't have to interrupt your creative flow by separating drums or vocals within your DAW - you can access them straight away. When browsing the catalog, if the stem is from the original recordings, it will be market with the tag 'studio'. If it isn't, it means we have separated the audio when we processed the catalog.

All stems are now only 1 credit as well!