Since I'm interested in uncompressed sound and "reference" recordings with the clearest and best audio I find titles in a variety of places and then try them out via Tidal. If it's just a track I just listen to it from there; if it's a whole album I may buy it. There are cases where even though I don't like the music the sound is so spectacular that I get it even though I might not like the music that much. This works since I listen either through my Oppo PM-1's or my GoldenEar Triton Ones. A great recording makes me feel that I'm at a live concert. Since I go to a lot of concerts I can easily compare what I've just heard in a concert with a recording of that same track by the same artist. So I'll just crank up Tidal on the drive home from the concert and listen to that artist's recordings to see how well it compares with the live version and then play it on the Goldenears via my Oppo and Tidal when I get home.
Places I look:
1) Search Amazon for "reference recordings".
2) Look at websites that review home theater, audio, and audio recordings. Since these guys review equipment and recordings for a living they get recordings from everywhere and have a lot of experience in evaluating the best sound. For example a headphone reviewer might mention that the first test track he goes to for bass response is "Sleep like a Child" by Joss Stone. Or for midrange "Murder in the Red Barn" by Tom Waits. These are tracks that you almost never ever hear on mass media streaming sites or radio. Is
Abbado Conducts Mahler Symphonies 1-7 [Blu-ray] the greatest classical recording ever made? At least one reviewer and classical website says so.
Places I look:
Audiophile Audition
SoundBard
The Audiophiliac
Computer Audiophile
"Best Headphone Test Tracks" Forbes
AudioWorld Online
Classical CD Review Which has a page of "Sonic Hall of Fame"
InnerFidelity
Stereophile
Analogplanet
Hometheater review
hifiplus
avsforum
audiostream
sound and vision
3) DTS demo disks on E-Bay generally have some tracks that have incredible DTS-MA audio.
4) Tidal has a playlist with what's new that week
For music that I just like I use
5) Movie soundtracks. Peter Sarstedt's "Where Do You Go To My Lovely" was in a movie I watched a while back. If sound hound doesn't find it the credits usually work. [One thing I hate about Apple TV is that it hides the credits in Netflix.]
6) I heard someone in a parked car listening to something I liked, turned on sound hound and found "Lucifer's Eyes" by T.O.L.D. which then led me to Youtube and Amber Run which led me to ....