A great way for a Blues record label to promote their catalog is to release a compilation CD. Relying on the marquee value of the bigger artists to promote lesser known artists who are also on the label. Here are the best collections from the best Blues labels.
1. Alligator Records 20th Anniversary Collection
This was a breakthrough record for Chicago's Alligator Records. Included are several classic artists along with contemporary acts. Classic performances by Hound Dog Taylor, Katie Webster, Koko Taylor. and many more. 
2. Alligator Records 30th Anniversary Collection
Alligator records continues it's compilation tradition with a collection of the labels latest releases. Short on the historical value of earlier compilations, this is still a rockin' record.
3. Mucho Mojo: Best of Fat Possum
Fat Possum's artists come right out of the mud, raw and real. This has proven to be quite a groove to many Blues fans. Short on big name artists with the exception of R.L. Burnside. The real deal!4. Chess Blues Classics 1957-67
The greatest Blues label ever has several compilation CD's. Most are done by artist, but this one includes all the greats.5. Blind Pig Records: 20th Anniversary Collection
Contemporary label has amassed an all-star roster of artists. Included are the greats like Buddy Guy, James Cotton, Carey Bell, and Otis Rush, and many more.