Any Musicians Not on Spotify?

Aside from Neil Young, Joni Mitchell and Gil Scott Heron/Brian Jackson, are there any other artists that are not on Spotify Premium?

I’ll be selling my vinyl collection in the coming months and converting the above 3 artists to other formats (mainly cassette) and want to know what other artists that I won’t be able to find on Spotify.  My collection is mostly classic rock, jazz, soul, and a small amount of classical.

Thanks!