Sega CD Model 1 shipped with a CD+G music demo disc type dealy... music video or two for each band + record company catalog #, etc to make it easier for you to purchase.
They also shipped with a "sampler" music cd.
I used to have a demo disc or two for the Sega CD.. one had Sonic CD demo, another had I think Road Avenger and another with like... Willy Beamish or something. A friend of mine has about 30 demo discs for the Sega CD. A few are repeats tho.