What are some cultures or bands that don't use the 12TET system and where can I find their music?
Expanding on @ggcg : That European music is absolutely 12TET-oriented is a notion that is not accurate
Violin intonation recommendation default pythagorean adjust chords towards just
Waldstein's third mvt. has, I believe, 17 bars with the pedal to be held down. Try this on a ET and it will quickly turn to a blur. Performed on a Young or Vallotti, it becomes an orchestral landscape https://www.pianostreet.com/smf/index.php?topic=39288.50
I can assent to this (almost) – I don't have access to a Valloti/Young tuning – but with Werckmeister or Kirnberger one can keep the pedal depressed as Beethoven indicates which is messy with ET.
Equal temperament "destroys everything" Note 100% western setting
Bach did not promote Equal temperament
Staff notation is not ET but closer to meantone ie there is one notion of whole tone (unlike Just's two) but C# is not 'spelt' same as Db. A pure 12 TET notation would be like midi numbers!