Orbis (British subsidiary publishing house of De Agostini Group)
The Blues Collection
The Classical Collection
It seems that many recordings are credited to fictitious artists. See Budget recordings of Alfred Scholz.
There is a review and listing of this series here.
There is a complete listing here.
A little more information about the series.
The Musical Collection
There is a complete listing here
DeAgostini which acquired Orbis Publishing in 1999 seems to have also been issuing some of these collections.