These shows out of roughly 100 I watched are the best choices in what you are looking for
Baccano
Each of the stories in the series involves several unrelated plots intersecting and crossing each other as events spiral further and further out of control. Immortal alchemists, mafia operated speakeasies, and many other elements of pulp fiction mashed together for a world straight out of the movies
Claymore
In a world where humans coexist with sentient monsters called Yoma (妖魔?) that feed on human innards, an organization has created an order of half-human, half-yoma warriors to protect humans from the yoma, for a large fee. The people of this world have dubbed these warriors "Claymores" based on their swords. They are also referred to as "Silver Eyed Witches", based on their appearance and seemingly cold nature toward others. Each Claymore has a rank number witch is based on their strength and ability. There are 47 ranks corresponding to the number of regions of the land/world.
A Claymore known as Clare saves a small town by killing a Yoma living there, and meets Raki, a boy whose parents were killed by the Yoma. Out of gratitude, Raki ends up following Clare from town to town during her Yoma-killing jobs. The two travel together until they are separated when Clare is forced to battle a sadistic Claymore named Ophelia. Before parting, Clare promises to find him if she survives. The story becomes a tale of revenge, as Clare seeks to confront someone from her past.
Monster
The series follows Dr. Kenzo Tenma as he pursues a young psychopath/sociopath named Johan, whose life Tenma decided to save over the mayor's. Johan grows up with a "monster" in his body which causes him to have a split personality; a gentlemen and a emotionless murderer. Dr. Tenma feels responsible to rid the world of Johan, as it was he who saved Johan's life. The story rapidly progresses through a number of locations: it starts in Düsseldorf, Germany, passes through Berlin, Frankfurt, Munich, Wiesbaden, cities in the Czech Republic such as Prague, and other cities and villages.