Yep there is a huge market - and lots of providers have risen to meet the demand. But there may well be a gap for you.
These are just the ones I've used myself:
Holosync (Centerpointe - pure entrainment)
Hemi Sync (Munroe Institute - hypnosis, MetaMusic)
Brain Sync (Kelly Howell - great for guided mediation)
Mind Sync (pure entrainment)
Unexplainable Store (pure entrainment)
Xphirience (new type of entrainment - very buzzy)
Relaxation-CDs.com (guided meditation, sounds)
I focus on promoting
brainwave entrainment (binaural beats, isochronic tones) on my website:
Top Binaural Beats MP3s for Lucid Dreaming and Deep Meditation - to me, they make simple hypnosis recordings feel outdated. But if you combine hypnosis/guided meditation with this kind of entrainment, that's when the magic happens.
And remember there is brainwave software that enables people to make their own tracks using a library of sounds, entrainment tones, even their own subliminal suggestions. This might even be how you plan to make yours, if you have the commercial license.