If you liked
Death Note
|
...then you might like
Code Geass: Hangyaku no Lelouch
|
The similarity here is quite obvious. Hyper-smart main characters are bestowed with a special power, which they then make use of to change the world to their liking, through plotting, planning and strategy.
If you liked
D.Gray-man
|
...then you might like
Soul Eater
|
Good organization versus evil organization, lots of characters with various weapons. Soul Eater is however much more lighthearted than D.Gray-Man.
If you liked
Trinity Blood
|
...then you might like
D.Gray-man
|
Both are darker, more serious action anime, focusing on the fight to preserve peace in this world and save the human race from evil. Where Trinity Blood has vampires, D.Gray-Man has demons.
If you liked
Bleach
|
...then you might like
D.Gray-man
|
Both are action/shonen series, with a group of good guys slowly fighting their way through the ranks of the bad guys, powering up in the process. While D.Gray-Man is often more serious than Bleach, they both have their moments of comedy to lighten up the mood when needed. Also, >100 % synch rate = bankai all the way.
If you liked
D.Gray-man
|
...then you might like
Naruto: Shippuuden
|
Shonen, with lots of great characters fighting against evil, as is typical of shonen anime. Whereas Shippuuden tries but fails to be serious, D.Gray-Man pulls off the serious mood with grace.
If you liked
Fullmetal Alchemist
|
...then you might like
D.Gray-man
|
Both have main characters with arms that functions as weapons. Both characters' childhoods featured a tragic loss for them, and the retribution they faced for trying to bring back the people they lost taint them to this very day.
If you liked
Bokusatsu Tenshi Dokuro-chan
|
...then you might like
Heppoko Jikken Animation Excel♥Saga
|
Two crazy anime series with seemingly little meaning aside entertaining those who are fans of crazy comedies and general nonsense. Also, both have extremely annoying opening themes.
If you liked
Trinity Blood
|
...then you might like
Blood+
|
Action, blood, a fight for a better and safer world, and of course, vampires galore!
If you liked
Blood+
|
...then you might like
Claymore
|
Both feature girls/women who has a hack-n'-slash fest, killing monsters with their swords.
If you liked
Blood+
|
...then you might like
Elfen Lied
|
Girl protagonists who kill a lot and spill a lot of blood. Both are poignant and moving throughout, with deep emotional struggles and bonds all over the place. Both have mutated human beings who take the role of bad guys pose a threat to humankind as a whole.
If you liked
Ayashi no Ceres
|
...then you might like
Blood+
|
Violence, drama and love. Emotionally deep female leads.
If you liked
Ayashi no Ceres
|
...then you might like
Fruits Basket
|
Drama, love and supernatural are prominent in both (though Fruits Basket is the more light-hearted of the two). Need I say more?
If you liked
Blood+
|
...then you might like
Amatsuki
|
Both shows feature protagonists who live normal high school lives, but are soon dragged into large, action-packed adventures.
If you liked
Amatsuki
|
...then you might like
Nabari no Ou
|
The protagonists of both shows are normal students who are suddenly drawn into another world (both literally and metaphorically), due to them possessing a very special power.
If you liked
Blood+
|
...then you might like
D.Gray-man
|
Both are action series with a darker tone to them, and both focus more on characters and are more character-driven than what normal action series tend to do
If you liked
Air
|
...then you might like
Kanon (2006)
|
Both are made by Key, and adapted by KyoAni. Both have a tragic feel to them, and they follow the "girl arc" formula with a boy coming to a town, meeting girls and their individual tragedies and troubles, each story arc focusing on one girl.
If you liked
Kumo no Mukou, Yakusoku no Basho
|
...then you might like
Byousoku 5 Centimeter
|
Both movies are similar in many aspects. Both are slice-of-life-ish (though The Place Promised strays from that path a few times), and the main characters are two childhood friends, a boy and a girl who have been separated for a long time. They have a distinct feeling of calmness to them, similar character designs as well as gorgeous art and animation. Both are directed by Makoto Shinkai, which is more than likely the reason for this similarity.
If you liked
Rosario to Vampire
|
...then you might like
Kanokon
|
Kanokon and R+V are similar in many aspects, first and foremost the ecchi one. Moreover, they have overly pushy "beauties" who assault the "unlucky" male protagonist, who by the way is a bit of a whimp. Both are also set in school, and have different supernatural aspects to them.