Brave Song -- Angel Beats!

Ichiban's treasure -- Angel Beats!

Chaoming り -- clannad

Day 々の遑-- clannad

Small palm-- clannad

Hourly を moment む呗-- clannad

Qingming Cherry Blossom Festival-- clannad

every time you kissed me -- Pandora's Heart

The Sea of ??Memory--Day on Campus

The Reason for Tears--Day on Campus

あなたが...いない--Day on campus

Kun no memory--Hakuo Oni

Akanekora Yuan--Hakuo Oni

Jun に世け-- I really want to tell you

Cold and cold house-- K

Bird poem-- air

one more time, one more chance--second speed Five Centimeters

Release My Soul -- Guilty Crown

stories -- Lelouch of the Rebellion

secrect base -- Unknown Flower

Smoke--This is not an anime Japanese song but it is very good

ねぇ--The scarlet film

あなたがいたsen--Fate stay night

In fact, sometimes some of them don't sound so sad, like the poem about birds, but after watching the anime, it feels completely different. They are all given one by one. I hope you will adopt them~