I could probably list more later. Also, do you care about vocals? Cause I know some songs that are good, (well, to me) that have vocals and without.
桃花恋情 – TЁЯRA (https://www.youtube.com/watch?v=vctBh5RM2ys)
not eternity – 猫叉Master (https://www.youtube.com/watch?v=hYOZVh3lt8Q)
Mizu no Madoromi – Origa (https://www.youtube.com/watch?v=iqFy9S_3L14)
Mizu no Madoromi (Russian Version) – Origa (https://www.youtube.com/watch?v=epmzDxsS4kc)
electric universe – Eiko Shimamiya (https://www.youtube.com/watch?v=VIUKEHpUPTQ)
Asunaro no Ki – Eiko Shimamiya (https://www.youtube.com/watch?v=T1pJ2VmkIKI)
Mouth On Fire – Yoko Kanno (https://www.youtube.com/watch?v=WceOm5Dn9vg)
流砂の嵐 (Long Version) – 劇団レコード (https://www.youtube.com/watch?v=F02gd4oTZaY)
Chinese – Mario Freaks Orchestra (https://www.youtube.com/watch?v=sxFEyVGg1hE)
Pretty much anything Eiko Shimamiya makes is great IMO if you like J-Pop. Same with 猫叉Master. He does mainly instrumentals.
https://www.youtube.com/watch?v=lXsgOuFVV_A
https://www.youtube.com/watch?v=xDEpGk5GJ0I
https://www.youtube.com/watch?v=ZkwzHx6K6Js
https://www.youtube.com/watch?v=U1PqTUUs8mY
https://www.youtube.com/watch?v=LKZDw4JQW7k
https://www.youtube.com/watch?v=9uGaffGU3Ks
https://www.youtube.com/watch?v=qbv7RckrjTw
https://www.youtube.com/watch?v=jzcQqjXSZXA