 If you liked
.hack//Sign
|
 ...then you might like
Elfen Lied
|
Both anime centre around a young depressed protagonist who hates the world. Both share themes such as family violence and school bullying, except that .hack//Sign only implies these themes, while Elfen Lied shows them; Elfen Lied depicts gore and nudity which might be considered offensive, while .hack//Sign is family-friendly and doesn't even has a slight nudity or fanservice.