I still listen to Needless soundtrack to this day, it has a very virtuoso vibe with it’s guitar solos.
Gurren Lagann has a lot of great music. Viral’s theme in particular is a banger.
Girls Last Tour
impeccable vibes
FLCL
Cowboy Bebop and Samurai Champloo
Any anime with Kensuke Ushio as the composer, most notably Silent Voice and Liz and the Blue Bird with prepared piano. He also composed the soundtrack for Dandadan and Devil May Cry
The ones with Kevin Penkin on the OST. There’s at least two of them now (Made in Abyss, Tower of God), so I guess they’re not unique anymore, but hey
Shield Hero as well. And his music is definitely the highlight of that series.
Does the Macross plus Sharon Apple qualify?
This is the answer. One of the best anime soundtracks ever.
Trigun and Cowboy Bebop for sure.
Ghost In The Shell: Stand Alone Complex
Also up there:
Macross Plus
Serial Experiments Lain
Teknuo no Escaflowne
Tenchi Muyo! RyoOhKi
Yes yes I am in fact old.
Devil man crybaby on Netflix. That soundtrack slaps
maybe Jojo
(I watched only ~10ep.)
Clannad
I think most animes, which are based on visual novels, have unique soundtrack, so Steins;Gate maybe too.
Tom and JerryIt had full it’s soundtrack like in this video (I just have yuru yuri example)
Are there anime with full it’s soundtrack like in Tom & Jerry, i.e. where every action is music?
That’s a pretty difficult question without examples or some details on what you’re looking or.
Do song covers in non-music anime count as unique? Soundtrack for The Rolling Girls contains covers of The Blue Hearts (including Stones with a great Shamisen solo).
Girls Last Tour has Song of Raindrops as an ED to one of its episodes - it consists of vocals, soft beat and sounds of dropping water.
I am not sure what you define as unique soundtracks, but Bleach and Solo Leveling come to mind as possible answers for myself.
