>>4452329 was my first thought. Here's the rest of my weeb playlist. Ironically I don't watch anime at all, japs just write good instrumental music. They're loosely ordered by darkness/intensity (Yoshimura is ambient/easy listening, Worlds End Girlfriend is experimental post rock, Kashiwa is in between). Hiroshi Yoshimura - Soundscape 1: Surround (best yoshimura imo)
https://youtu.be/MojW0fVaaFEHiroshi Yoshimura - Flora
https://youtu.be/j6n4FpHbqZsRaflum - ???/Melodies Of Forest And Springs
https://youtu.be/rqFpbo_K2EgKashiwa Daisuke - Program Music I
https://youtu.be/YeT0t1C_y20Kashiwa Daisuke - Program Music II
https://youtu.be/grDODVw-VbkKidkanevil & Daisuke Tanabe - Kidsuke (fun)
https://youtu.be/sugAl4nM778Kidkanevil - My Little Ghost
https://youtu.be/QRffT1dqqmgWorlds End Girlfriend - Dreams End Come True
https://youtu.be/62u9gprlcBYWorlds End Girlfriend - Hurtbreak Wonderland (masterpiece)
https://youtu.be/WoWRUkEaR7kWorlds End Girlfriend & Mono - Palmless Prayer/Mass Murder Refrain (very mellow but dark)
https://youtu.be/wqdKXcR_UnsWorlds End Girlfriend - Bohemian Purgatory
https://youtu.be/kofmDnZfxMwMutyumu/??? - ???
https://youtu.be/DXsqrr13n40 
