Here is Ranker's list of the best seinen anime and manga, with help from voters like you. Just so everyone is clear, seinen isn't as much a genre as it is a demographic. Seinen anime and manga cater to adults ages 18 and older, so the content is often mature and violent. Seinen can be many genres, including sports, action, mecha, and more. The series we've listed here are considered to be the top seinen anime or manga, but we're not always perfect with our choices. If one of your favorite series is missing, please add it to the list so others can vote on it too!
In most cases these titles are both anime and manga, but some like Sun-Ken Rock are exclusively manga. Some of the best classic examples of seinen series include Ghost in the Shell: Stand Along Complex, Berserk, and Elfen Lied. We've included new 2014 seinen anime too, such as Black Bullet and Hamatora.
http://www.ranker.com/list/best-seinen-anime-and-manga/ranker-anime,
Psycho-Pass
Kara no Kyoukai
Speed Grapher
Psycho-Pass
Darker Then BLACK
Ghost in the Shell: Stand Alone Complex
Steins;Gate
Durarara!!
Elfen Lied
Baccano!