When Black, Potter, and Wormtail become animagi for Lupin when he transforms. Subtle but extremely touching.
Harry's Hungarian Horntail tattoo "NOT MY DAUGHTER, YOU BITCH" Gred and Forge "...That's my nickname." "There's no need to call me sir, professor." Harry asking Nearly Headless Nick about ghosts St. Mungo's "I don't think you're a waste of space." "They guard the wizard prison, Azkaban!" (related: "REMEMBER MY LAST, PETUNIA") Visiting Godric's Hollow Harry's first time at the Burrow "King's Cross" "Is he alive? Is Draco alive?" The battle at the Ministry (special mention to the visitor badges) Snape vs. the Marauders' Map Neville's boggart I'M SORRY I KEEP EDITING IT THEN GOING TO LEAVE THEN EDITING IT
Related: Dumbledore's farewell in my opinion is one of the greatest pieces of music to ever hit a movie. Great song to just walk and think, kinda get lost in the music. Man, what a killer song.