Back-up Vocal~ I know there are Backing Tracks albums featuring only drums and bass guitar. They do exist. They are mostly advertised in music magazines or sold at guitar stores, They are mostly for instruction and not the kind of thing a standard record store (do we still even have those anymore?) would carry.
I have a leg-long list of rhythm sections I wish would release Backing Tracks CDs. One principle team stands out. Broken record time for those who know me: Ian Mosley (drums) and Pete Trewavas (bass) of Marillion have been my favorite duo for years, and I would LOVE to see them unleash a CD of their talents. They have VOLUMES they could teach young bands about the communion drums and bass MUST share for music to really work.
Finally, it has not escaped my attention that Manny SPELLED WORDS here. Proof it can happen.