I'm really getting into fantasy/scifi shoujo right now, particularly Hanatsuki Hime and Shounen Doll. I'd love more manga where the guy isn't human, though I'm not picky what he is (Angel, demon, robot, pet-turned-human, whatever) Thanks!

There are so many!!!! I love fantasy as well! 🙂

Completed:

TEN NO RYUU CHI NO SAKURA
Black Bird
Kanata Kara
Midnight Secretary
LOVE CRUISE -Ryuujin-sama to Oyome-sama Oneshot
Please save my earth
HANA TO AKUMA
Kamisama Hajimemashita
Love Monster
Immortal Rain
Sarashi Asobi
Merupuri
Toraware no Minoue
Dakishimete! Noir
FULL MOON JOKER
Akuma no Kuchizuke
Watashi no + Okusuri

Also try these tags:
There are many more wonderful stories

http://www.mangaupdates.com/series.html?category=Unorthodox+Male+Love+Interest

http://www.mangaupdates.com/series.html?category=Human-Nonhuman+Relationship

There should be a whole bunch of stories revolving around such relationships, but the ones coming to my mind are:

• The Bride of the Water God - If you don't mind Manhwa and the plot getting a bit messy by times, then the drawing style and twists within story will make it surely worth a look.

• Zettai Kareshi - A classics already.

• Tonari no Shugoshin - A rather unique pairing, since the male leads appearence is actually bound to a game card, which the female main gets into her hands by chance.

• Kazekaze no Hito - Likeable style of art and nice to kill some time.

• Death Edge - A pretty interesting story so far, that still makes me curious about the next chapters.

• Kare wa Diablo! - Funny, although the flow of things seems somewhat typical.

• Omae ga Sekai wo Kowashitai nara - More serious and sometimes a bit confusing.

• Bokura no Himitsu o Kyouyuu Shiyou ka - Maybe not a perfect match, but I liked those stories - and the guys probably could count as non-human.

• Akuma ni Itsukushimi no Te o and Wasurene no Language - Two oneshots. ^^

"It's like love is a bonus in your life. Even without it, I'm just fine. I don't feel like pointlessly searching for it. You don't have to make yourself unhappy." (Ookami Shoujo to Kuro Ouji)

"Why does it rain?" - "To create drama." (Drops (Andou Yuki))

You want Harlem Beat wa Yoake made

kurenai ouji
Vampire Knight
Dear
Youko x Boku SS
Kamisama Hajimemashita

Completed:

Mizu ni Sumu Hana
Destination Heaven Chronicles
Hiiro Ouji
Tokage Ouji
KARESHI WA DOBERMAN
wild wing
Ginrou no Sakura --> Same author as Hanatsuki Hime and Shounen Doll
Kindan no Koibito --->Guruguru Pon-chan Okawari oneshot
FEMININE WA UTAU
Fairy Cube
Absolute Witch
Mikan no Tsuki
SAILOR FUKU NI ONEGAI!
Apothecarius Argentum
Men Are Wolves?

Try these tags as well:
http://www.mangaupdates.com/series.html?page=1&category=Animal+Transformation

I got some more interesting titles for you:

Completed:

Boku wa Ookami
F.O.X
Bloody Kiss
BlackxBlack
GLOBAL GARDEN
Kon no Ki Konoha
Kemonotachi no Yoru
Beast Master
Eternal Sabbath
World End Garden
Hotarubi no Mori E --> Into the Forest of Fireflies' Light oneshot
Fuyu no Hana
Yoru no Kakaku
Another Kingdom
Eien Kamoshirenai
Akuma ga Hareruya
Cinema Empire
ANTI-GRAVITY BOY
Akuma no Puzzle
Blood Hound
Fruit Basket
Gekka no Kimi
Fushigi yuugi
Princess Tutu
Pretear
Tokyo Mew Mew
Masca
Angel at War
Hoshi ni Naru hi

These are ongoing:

Brundage no Mahou no Shiro
Youren Soushi - Koyoi, Kimi to Kiss no Chigiri o
Futari no Himitsu
Phoenix Flames: Campus Secret Seal
Abide by the Wind
Prince of the Night
Akatsuki no Yona
Purple Eyes
Caramel Kiss
Love Probation Witch
Tao Tie Jie
Genjuu no Seiza
Platinum Garden
Bird of Youth
Ciel
Oh, My Romantic Kumiho
Reimei no Arcana
Queen's Knight
Ayakashi Hisen
Silver
Kurobara Alice

As I remember titles, I will keep posting them:

Completed:
Land of Silver Rain
Vision of escaflowne
SHINIGAMI LOVERS
Model
Tenshi no Hitsugi
Arcana
Full Moon o Sagashite
Vampire Rose
Kamikaze Kaitou Jeanne
Hyouketsu Kiss Mate
Divine Melody
Barairo My Honey
Yasei no Bara
Swan Prince
Mou Hitori no Marionette-->This one technically counts cause the guy is not normal.
Kindan no Koi wo Shiyou
Kindan no Koi de Ikou
Zoku - Kindan no Koi wo Shiyou

Ongoing:
Anata ni Hana o Sasagemashou
Siesta
Evyione
F.O.X II
Michibata no Tenshi
Tokyo Innocent
Rure
Song of the Doll
Crystal Dragon
Innocent Dragon
Tokyo ESP

I got some more titles for you:

Completed:
Anata e no Crescendo-->Mistake oneshot
Le Masque
A Million Pound Love
Bokura no Himitsu wo Kaihou shiyou ka
Kyuuketsuki to Boku
Tenshi no Naka ni Akuma Ari
Normal City
Sora wa Akai Kawa no Hotori-->Technically he is not a normal human
Ao no Fuuin
+Anima
Karakuri Odetto
Soraoto
Kuroneko Renai Kumikyoku
Slice of Black Chocolate

Ongoing:
Watashi no + Okusuri
Tsubasa wo Motsu Mono
Liselotte to Majo no Mori
NOBODY KNOWS (LEE HYEON-SOOK)
Lost In London