Shostakovich Tenth Symphony Karajan/Berlin or the previously mentioned Reiner/CSO Scherazade.
I listen primarily to digital and the OP is analog but the above are 2 LPs that sound great and the works test every bit of the orchestra. For organ I would find a good copy of E Power Biggs Bach at the Thomaskirche.
I can’t resist telling the OP that yes, streaming and all forms of digital media can sound ‘as good’ as vinyl, and IMO usually better