Hm...try In the Arms of an Angel - Sarah McLachlan
-Concrete Angel - Martina McBride (I recommend watching the music video too, it adds to the feels)
-Anthem of the Angels - Breaking Benjamin
-What Hurts the Most - Rascal Flatts
-100 Years - Five For Fighting
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https://www.youtube.com/watch?v=RwUGSYDKUxU Imagine - John Lennon
-Faithfully - Journey
-The Fighter - Gym Class Heroes ft. Ryan Tedder (old song, but who cares? It's great)
-If I Die Young - The Band Perry (also old, but also great)
-Chasing Cars - Snow Patrol
-This Love, This Hate - Hollywood Undead
-King - Lauren Aquilina
-Last Song - Yamai
-Snow Flower - Maria Yamamoto
-Pandora Hearts's OST - Will
-Represent - DJ Okawari
-Love-Distance Long Affair - Deco*27 ft. Topi
-Requiem of Red (a song from an anime. Idk about you, but it makes me pretty sad. Also, idk if you'd need to watch it to understand the sadness. When it gets near the middle, that's where goosebumps start to rise)
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https://www.youtube.com/watch?v=3AhZzH9Qr0E Vocaloid, don't know if you like this kind of stuff
Basically any sad Vocaloid songs (
https://www.youtube.com/watch?v=O0TtDeDiHcE The Lost One's Weeping - Kagamine Rin) are a guarantee, just pay close attention to the lyrics.