Leaving Hogwarts is by John Williams and honestly one of my most absolute favorite Harry Potter soundtracks (and that's saying something because all of them are so amazing). It plays at the end of the Sorcerer's Stone and in the epilogue of the Deathly Hallows Part 2. I've checked some youtube playlist for the soundtracks of DH Part 2 and it's not there. But it's because most consider it as more of a SS song because it's by John Williams and was first in the first movie. You can also hear a bit of it in the end of CoS. And if you pay close attention you can hear a bit of a Hedwig's theme in Leaving Hogwarts. So Leaving Hogwarts plays when the trio and Ginny's kids are going to Hogwarts. I cried during that scene and sometimes I cry just when I hear the soundtrack because it brings back all the memories. U HAVE TO LISTEN TO IT AND CRY WITH ME!