If you liked
X
|
...then you might like
Drifters
|
Both are about two different factions with conflicting morals and different ideologies going to war with each other.
If you liked
Death Note
|
...then you might like
Claymore
|
Plus, both are animated by Madhouse and have opening themes performed by Nightmare. And Guilty Sky kind of sounds like Eraser Rain.
If you liked
Cardcaptor Sakura
|
...then you might like
Death Note
|
Both of these shows take the concept of "ordinary school student finds mysterious magical book and sees its powers first hand, changing their lives forever and befriends the magical creature that originally owned said magic book and can fly and likes to eat. A lot." And then each show goes in complete opposite directions with it. And they both have widely reviled "Americanized" versions too; CardCaptors and 2017 Netflix Death Note. While the tones and feels of each show are complete opposite to one-another, they do have somewhat similar setups that both involve ordinary school students finding mysterious books with magical powers and befriending the strange creatures that originally owned them. And they're both animated by Studio Madhouse.