Guaranteed to suit your taste, give it a listen.

The accompaniment of the Final Fantasy song, "Su Enemy - INSTRUMENTAL" is super sad.

Shiina Harumi's "Hua Quan" has an eerie and eerie style that adds to its tragedy. I think this song is definitely comparable to "Su Enemy".

Music for the movie Millennium Crane by Liang Bangyan.

Himegami "Quiet Alone"

"Departure (Piano+Acoustic Guitar Version)" comes from the album "るろうに剣心-Meiji Kanke Romantic Tan-" COMPLETE CD-BOX

Shinji Orito "-风をwaiった日" Soundtrack of Snow Maiden

Anan Ryoko "Refrain"

Eiji Mori "Hyakki Yakōsho" Hyakki Yakōsho o.s.t

Isomura Yukiko's "The Street Where the Wind Lives" was used as the soundtrack for the new Gisaeng

Hell Shoujo's "Aizen" is also very sad.

The violin version of Koji Takanashi's "Hakuei" is more melancholy, and the soundtrack of "Sorrow of the Past" Fairy Tail

Wada Kaoru's "KIRARA キララ" "The Miko Kikyo of Misfortune" "Love" Inuyasha Soundtrack

En no Sora OTS "Far Sora - (ヨスガノソラメインテーマ)"

"Fate" Fairy Tail

Jeon So-yeon "Lovesickness ( With Ocarina)》

大俀あすか《Honesty》电波女とYoung man オリジナルサウンドトラックVol. 1

Hirahara Ayaka ""Reset"～"ありがとう"バージョン～》

Naruto - "Moonlight Talk"

Kawashima Noriko's "Blue Sky No Walking Side - Hakuoki" is both instrumental and very sad.

Key Company "Shioming りⅡ" CLANNAD Original SoundTrack DI

すたじおみりすteam L←→R "Maple Leaves Fall"

Kawai Kenji "Lonely Pilgrimage"

Uematsu Noyasu's "スカーレット" album Narcissu Soundtrack

Sahashi Toshihiko's "Jun's Servant's Thoughts"

Shikura Chiyomaru "-Rain's Rain"

Ma Zhijun's "theme of SSS" is a different kind of sadness.

That’s it, I feel bad if I listen to it too much.