Monster, Rainbow: Nisha Rokubou no Shichinin Recommendations
Both shows show the darkness that some people can show, but both also show the kindness that people can show.
But thats all that is similar.
Monster is more mystery while, Rainbow is a calm story about making it through hard times with....
They are both deep anime more for adults and with a taste of shitty situations shitty world but also a satisfying bright side of life
Story wise, they're very far apart, but both shows have a dark and gritty atmosphere, and both delve into the darker side of life and the human condition. The stories told in each are mature and intelligent, and the cast of characters are very strongly written and well-developed for the most part.