Atelier series is pretty relaxing in terms of both story and BGM, and uses flute and acoustic guitar pretty often, which hits the spot if you've finished working for today and not in the epic mood.

• (Atelier Escha & Logy) The Red Sky
• (Atelier Escha & Logy) All Under One Sky
• (Atelier Sophie) Glistening Lake
• (Atelier Firis) Tale Spinning Journey ~ Night

I also like how music contributes to the atmosphere of .hack//G.U., which may have aged poorly as a game series, but it has the fantastic setting of what science-fiction writers from 90s imagined online worlds to be in 2017. The music here is as slow and sedate as the flow of time in "The World" itself.

• Desktop
• Eternal City Mac Anu
• Dual City Breg Epona