Got this list online for heartbreaking sad anime(s):
1. Violet Evergarden
2. Angel Beats!
3. Your Lie in April
4. Banana Fish
5. Anohana: The Flower We Saw That Day
6. Cyberpunk: Edgerunners
7. Tokyo Magnitude 8.0
8. WorldEnd: What do you do at the end of the world? Are you busy? Will you save us?
9. Plastic Memories
10. Clannad: After Story