The soundtrack by Joe Hisaishi in the Miyala animation! !

clannad's small palm, blue sky, tide sound...

Guilty Crown's Eden

Gintama's episode お前の大事な连中ならいる だろお前の中に

The OP of Fairy Melody: Elfen Lied-Lilium ~coteesh remix~

Steel-made БРАТЬЯ(ブラーチヤ)

EVA’s Wing をください

One more time, one more chance at five centimeters per second

Naruto's episode Grief and Sorrow

The sad day in school しみの向こうへ

Lelouch of the Rebellion's interlude stories

Honey and Clover's interludes Yawarakana Jikan, Yotsuba no Clover, Yamaai Ame

And Apollo on the Slope 's ED, The Gray Water Sunshine of Rotary Penguin Tank, Fate stay night's ED Deep Forest, and the unknown secret base (these don't seem to have sad melodies, but I feel quite sad when I listen to them).