If you liked
NOiSE
|
...then you might like
Mercy
|
Similar in tone and art style; featuring a shady taciturn mc laying waste to demonic looking entities, a subplot featuring a secret society of religious fanatics and a distinct feeling that this is the beginning of a much longer story.
If you liked
Yokohama Kaidashi Kikou
|
...then you might like
Tabi to Gohan to Shuumatsu Sekai
|
A gynoid left by her creator goes though slice-of-life adventures in world of humanity's twilight. The premises are nearly identical.
If you liked
Mushishi
|
...then you might like
Mononoke
|
Mushishi is more contemplative and Mononoke is darker in tone, but their semblance is undeniable.
If you liked
Blame!
|
...then you might like
Biomega
|
If you've read one, you'll pretty much end up reading the other.
If you liked
Aku no Hana
|
...then you might like
Yakedo Shoujo
|
The darker side of highschool-set MPDG exploration.
If you liked
Blood Lad
|
...then you might like
Anagle Mole
|
Both are goofy mangas where a teenage boy monster who’s in trepidation of humans ventures to a Japanese city from an underground demon world (resembling a human one but more vicious).
If you liked
Serial Experiments Lain
|
...then you might like
Boogiepop wa Warawanai
|
I'm sure everything about similarity of those two wonderful non-mainstream anime was said already so I'm just adding a vote.
If you liked
Mushishi
|
...then you might like
Bartender
|
The atmosphere is similar--calm, meditative, leisurely-narrated, various stories of different people are told within each episode. Mysterious main characters, they're masters of their craft. Bartender and unseen-otherworldly-creatures expert - you don't see it at first, but the core of their job is to help people and they do so with what they know best.
If you liked
Gantz
|
...then you might like
Gyakkyou Burai Kaiji: Ultimate Survivor
|
Main characters are pulled out of their normal lives and learn to value the price of life through incredibly tough physical and psychological challenges.