As in the main character is something other than human. Demon, Shinigami, Angel, Dog, robot, etc.. Or at least the person whom the main character is in love with non-human.

Anything will do but yaoi.

I'd prefer if the main character was male.

Onegai Teacher

human boy, alien female

| One Punch Man | Noblesse | Nanatsu no Taizai | Gun x Clover |

My Sweet Dragon, the boy is a dragon god, its not fully sacanlated tought and the releases are really slow..... and Her Majesty's Dog, the boy is a guardian demon...

happy world - Human boy, Girl Angel
inukami!
steel angel kurumi
chobits

and some that i forgot hehe sorry

oh yeah!! rosario + vampire and rosario + vampire II

[img]http://i415.photobucket.com/albums/pp235/carlQT_2008/Tsunayoshi_sig_by_Radic4L.png[/img]

Kizaru, the only person who can say Ben Beckman without his lips touching

just CARL is fine

Karin Human boy, Vampire female.
Ookami to Koushinryou Human Boy, Human/wolf mix female

Chobits totally fits!!! It's great! And I don't even like ecchi!

Some suggestions:

DearS Alien
Kurozuka Vampire
Fruits Basket well they are humans but can transform into animals.
Akuma Jiten
Vampire Juujikai Vampire/Dhampir
Ai-Ren Robot
Mahoromatic Robot

What I like in Trivial Pursuit style. Pick your category:[img]http://i379.photobucket.com/albums/oo233/Reid4891/Manga/trivia-1.jpg[/img]

Chobits
Zettai Kareshi
Vampire Knight

The Bride of the Water God
Black Bird
Bloody Kiss
Love Monster
Vampire Knight
Zettai Kareshi

Chobits
DearS
there's a lot

Chrno Crusade
I Wish...
Midnight Secretary
Superior
Hanatsukihime

can both be non human?..vampire knight but doesnt really focus on romance that much Yuria 100 Shiki...

i was nervous at first it was big & long & went straight up i had to try it i eased onto it & liked it! i went up & down on it.... i love escalators now! 😀

(great onizuka ftw)

Inumimi
wolf and spice
To-LOVE-Ru
Omamori Himari
My Balls
Crimson Grave
Happy World
3x3 eyes
Erementar Gerad
Eureka Seven
Kitsune no Yomeiri

[img]http://i590.photobucket.com/albums/ss350/afikolami/untitled3.png[/img]

Err... all my suggestions are shoujo manga/female protagonist. Sorry in advance if that's not your thing.

All the series I thought of are actually by the same mangaka, Suzuki Julietta. Karakuri Odette is the first one I thought of, though I don't know for sure if it has any actual romance. But it's a really charming story about an android girl and her various friends, some human and some not. I definitely recommend it! Akuma to Dolce by the same mangaka involves a human girl and a demon lord type guy.... and her most recent story, Kamisama Hajimemashita is about a human girl and kitsune spirit (i believe). All of her works are really fun and light hearted and, I would say, more interesting than many other shoujo manga out there.