@chocolatte-cup probably it's the same singer. I don't remember this song in the anime also

Serial Experiments Lain related

Duvet [Cyberia ReMIX]

This one actually comes from Evangelion "PianoForte" a collection of songs (almost all arranged as jazz) for piano. Enjoy.

You can find missing songs in SEL playlist here: archive(dot)org/details/serialexperimentslainostcollectionflac