Completed:

NHK ni youkoso! [welcome to the NHK] [Comedy]
Pani Poni Dash! [Comedy]
Azumanga Daioh [Comedy]
Jigoku Shoujo [Futakomori] [Drama/Horror]
Higurashi no Naku Koro ni [Horror]
Death Note [Supernatural/Horror]
Code Geass [Supernatural/Meccha]
Elfen Lied [Horror/Drama]
Peace Maker Kurogane [Historical/Action]
Le Chevalier D'Eon [Historical/Horror]
Ergo Proxy [Science-fiction/Supernatural]
Ichigo Mashimaro [Comedy]
Gunslinger Girl [Drama/Action]
Black Lagoon [Action]
Mushishi [Supernatural]
Excel saga [Comedy]
Kamichu! [not to be mistaken for Kamichama] [Drama/Supernatural] [Great Animations]
Full Metal Alchemist [Action]
Trinity Blood [Horror/Science-fiction]

movies:

Paprika [Drama/Near-Future/Supernatural]

ongoing:

Seto no Hanayome [Comedy]
Hayate no Gotoku! [Comedy]
Lucky Star [Comedy]
Higurashi no Naku Koro ni Kai [Horror]
Devil May Cry [Horror]
Darker than Black [Action/Science-fiction]
Zombie-Loan [Horror/Supernatural]
The Skull Man [Supernatural/Horror]
Wangan Midnight [Cars/Initial D]
Ichigo Mashimaro OVA's [Comedy]
Hellsing Ultimate OVA's [Horror]
Chocotto Sister [Comedy]
Moe-tan [Mahou-Shoujo/Comedy]
Claymore [Action/Horror]