Can be from any genre. Mine is when an acoustic guitar comes in towards the end of a song and totally changes or reframes the mood/energy (see “Money” by Widowspeak)
I like short intros with only vocals like “Hush” from Stick to your Guns.
I quite enjoy it when songs sneakily build up, starting out with a mellow rhythm and after a few minutes, you find yourself in the middle of an epic solo on top of this thick carpet of rhythm, and it’s all very much over the top, but it works, because of that slow build-up.
I used to get annoyed by pink floyd songs being so slow. I now realize it’s so much more powerful and overwhelming because it started slow
I don’t know you or your general taste in music but if you ever want something a bit more modern yet als doing the ‘start slow until you made a wall of sound out of it’ thing, I highly recommend you check out the band Motorpsycho! Pretty much every album they made in the 90s and early 2000s have always at least one great song which will build and build and build up to a great crescendo. Their other stuff is absolutely great too! Their song Vortex Surfer got played for 24 hours on new years eve (I think it was 99 to 2000) on a Norwegian radio station.