People often share files in open directories on their websites. You can find these files by searching on Google:
<<SONG NAME>> “Index of” “.mp3” “Last modified”
However, there's now a lot of SEO spam trying to hijack traffic for people searching for these files. Of course, you should avoid downloading from sites that have not been authorized by the copyright holders to redistribute the content.
You may find better luck simply finding the song on youtube and downloading it as an audio file.
Downloading from Youtube
- Download yt-dlp https://github.com/yt-dlp/yt-dlp/wiki/Installation
- Search youtube for the song you like
- Run the following command, substituting your youtube url. Make sure you only have the v= part, and not any parameters related to playlists
yt-dlp -f m4a 'https://www.youtube.com/watch?v=amrKGuuSZlg'
It should download the m4a file, which is an audio file similar to mp3. For example here is a successful output from the above command.
[youtube] Extracting URL: https://www.youtube.com/watch?v=amrKGuuSZlg
[youtube] amrKGuuSZlg: Downloading webpage
[youtube] amrKGuuSZlg: Downloading android player API JSON
[info] amrKGuuSZlg: Downloading 1 format(s): 140
[dashsegments] Total fragments: 1
[download] Destination: CHRONO TRIGGER - Secret Of The Forest ｜ VGM Acoustic [amrKGuuSZlg].m4a
[download] 100% of 4.19MiB in 00:00:00 at 13.71MiB/s
[FixupM4a] Correcting container of "CHRONO TRIGGER - Secret Of The Forest ｜ VGM Acoustic [amrKGuuSZlg].m4a"