There's an infinite number of them. Here's some off the top of my head. (you'll notice they become links after 5 videos - that is apparently the rule - no more than 5 vids per post)
Gladiator ending (soundtrack really enhances it)
King Kong 1976 (slow slaughter of Kong). Can't watch the ending to this fantastic version of the movie. Unbearable.
Wuthering Heights 1939 (Death of Cathy. Sir Lawrence really bringing it.)
On Golden Pond (daughter/Jane making up with father/Henry - Art imitating real life rift between the 2), Jane mentions he started to tear up when she grabbed his hand, it was so real for them.
1:36:00 in
Memoirs of a Geisha
Chiyo throws away handkerchief (and her hope of ever having the one thing in life she wanted, the man of her dreams, man gave her the handkerchief when she was a child)
Also when little Chiyo is told of her parents death, and the little sweetheart biting her lip trying to be strong.
Logan (ending - daughter's reaction to it)
Age of Ultron (Pietro's death - actually thought Pietro was a punk, but Wanda's reaction was heartbreaking)
Infinity Wars (death of Gamorra) - Amazing music
End Game (in 1970, Capt America sees Peggy)
Thor 2 (Dark World) (Frigga's funeral scene)
Harry Potter and the Half Blood Prince (death of Dumbledore)