According to the search results on Zhihu, the songs you are looking for are as follows:

1. "MELANCHOLY", this is an English song sung by WhiteCherry. There is a female voice singing "ah ha ah ha ah ha" repeatedly.

2. "やわらかな光", this is a Japanese song sung by やまだ豊. In the song, a female voice repeatedly hums "Ahhhhhhhhh".

3. "Forthedamaged Coda", this is an English song sung by Blonde Redhead. It was used as the ending theme of the seventh episode of the third season of "Rick and Morty". There is a female voice humming repeatedly in the song. Sing "Ahhhhhhhhhh".

4. "When the Mountains Have No Edges", this is a Chinese song sung by Li Zongsheng. In the song, a female voice repeatedly hums "Haaah, ahhh, ahhhh".