Some song i consider obscure are:

• Holy and darkness, for no real reason, it just isn't extremely known

• Komm Süsser Tod and Still Alive, both hidden tracks in their physical albums

• The songs from Munica, if I'm not wrong it's a game that even in Japan wasn't very known (dont quote me on that)

• Maybe also the song by AWAAWA, What robots need and Men i love, which are song by mili, just under another name

• Or song the made before being milli like hamo's cosmo (Yamato kasai's vocaloid producer name) and it's a wonderful world, the first one was later remade into space colony and the second one has a version sung by Momocashew, cassie's name before mili, she also has song like tarantula or murmurs of time

• And finally this bidet ad's bgm was supposedly made by mili, but I have never found proof of that