There are many great recommendations above. My experience with the ones I know supports their inclusion on the list. Here are a couple I use to demonstrate my system and audition analogue components that haven’t been mentioned by others:
Art Ensemble of Chicago, Third Decade (first pressing)
Joan Armatrading, S/T (original release-not sure of pressing)
The Band, Stagefright (MoFi)
I’m impressed with the sound on my system of the recent Rhino High Fidelity reissue of The Faces’ “Ooh La La” and likely will use it for demos in future.

