I can't believe more people aren't bringing up The Rolling Stones. They have an absolutely enormous catalogue. From the mid-60s to mid-80s they were churning out album after album.

If you count electronic music and remixes of other people's stuff Paul Oakenfold also has a very massive library.

Coheed and Cambria have 10 albums all (except one) as part of a single concept and they're pretty close to 150, but I'm not sure if they're quite there. They also have a handful of non-album singles.