I found this playlist on spotify, It's all good with the songs but I found this playlist somehow includes so many Iyowa's album exclusives, even those that arent found yet.
The interesting part is that maybe It's not just the name what is listed about the song, because all of the exclusives (those who are grey out) have the full lenght of the songs, and I can confirm it because Hero Ga Inai Machi, has the identical duration to the copy I have.
My point is, the songs are published, but inaccessible because they are local files of the person who uploaded the playlist, I do not support piracy, but it could help us to get those songs which are impossible to get by conventional means today, as a method of “preservation”.
This would be the most interesting example included in the playlist.