What are your go to LP's for evaluating new gear or new tubes?

Steely Dan's Aja and Pink Floyd's Dark Side of the Moon

The Reiner/CSO Scheherazade, Joni Mitchell's Court and Spark, Ry Cooder's Paris, Texas

For me it is usually Opus 3's Test Record 1. Especially the first track, Therese Juel's Tiden Bara Går. Then Barbirolli's Elgar Cello Concert and Sea Pictures. Both are very well recorded (goes without saying for any Opus 3 recordings) and I know them intimately, which means I quickly pick up on differences in the sound.

I spent some bucks on high quality vinyl. Some sound a smidge better than streaming, but not enough for me to play vinyl when streaming is so easy.  Personal preference. I do have the Jennifer Warnes and Kacey Musgraves on vinyl.  James Taylor - Hourglass is another favorite.

The majority of the music that I play currently was discovered by streaming. I wouldn't even know about many of my favorite musicians without it.  If I really like a recording, I often buy the cd.  I bought the October Project cd directly from the band via Bandcamp.