15 [Similar Anime] Like 91 Days

It's an obvious reccomendarion, isn't it?
Probably you're right, but i want to say:

It is quite similar to Baccano in many ways. I'll keep this short: same type of storytelling, same atmosphere, this anime awakens the same feeling of anticipation as Baccano does, very tense, dark and interesting plot, setting of the story is in Prohibition-era in USA, mafia clans and wars included. It also looks like it will be brutal and it will involve a lot of vengance and character interweaving. 10/10 so far.

Mafia-centric, takes place in America, a revenge story, nothing to feel good about but lots of reasons to cry – if you are into that, then you will love them.
While 91 Days deals mostly with drug crimes and violence, Banana Fish touches on much heavier topics like sex trafficking and pedophilia, never graphic in nature, it's more a drama-thriller with less violence and younger characters than 91 Days, which shows gruesome murders in detail. Another similarity is the very realistic depiction of the Mafia, there is no romanticization or glamour to it, if you are searching for that then neither of them will be to your taste.
One aspect to note is that Banana Fish features a gay couple, but it's never up in your face and can be easily overlooked, while 91 Days has no romance or even vaguely non-platonic relationships.

While 91 Days is settled on the USA during the 20's, Joker Game is settled in Japan during the WWII. What makes them similiar? Well, these suited handsome men are really skilled on their own field. Somehow you will find the connection among them. You should take into account that in 91 Days you will see mafia members and how they settle their interests, while in Joker Game, as they are spies, they work unseen and unnoted, on a very stylish way.

Similar in tone when comparing the brutality and the harsh reality of the main protagonist lives, work, and overall society each where given. Also, both main characters were given "unfavorable" cards in their lives but decided to challenge them in an act that might seem futile to others. But in reality, it is not so much the act of rebelling but the significance of said rebellion which is expressed in each story.

Out of all the mafioso inspired anime entries out there, these two come the closest to capturing the very essence of the subgenre. The usual themes revolving around family, loyalty, revenge, and corruption are omnipresent.

The main character is very similar to Lelouch in the fact he is manipulative, has to go under a fake alias, wants to work out who exactly killed/injured his family, especially his younger sibling, and almost everything he plans goes exactly to plan. Both are geniuses, and the Mafia families are almost as ruthless as the Brittanian royal family. A definite watch.

Aside from these series being stories of revenge against three people that ruined the lives of the respective lead characters, there does not initially appear to be too much linking the two: 91 Days involves 1920's American gangsters, where as Gankutsuou is a multi-layered 'dish best served cold' saga involving French noblemen. But, by the end, the 91 Days scheme for vengeance turns out to be more complex than it first appeared...

Death Note's most pervasive and most well acclaimed element is the mental chess game that is battled between L and Light (kira). This dynamic is both complex and intense, with a pressure exuded between the cast that could choke the air out of you in anticipation.

Both of these are set around the same time period, they both have main characters that are pretty emotionless because of their past and they seek revenge. Like in 91 days, you can't trust anyone. It seems as if everyone has evil intent and both have a lot of violence and are pretty dark. They both have some funny moments though (especially Kuroshitsuji.)

Both have an eerie noir atmosphere. Lots of death in both, and characters with sad backstories and characters that die due to bad luck.

2 episodes in to princess principal and I already love it. The mood and color pallete remind me a lot of 91 days. While I do admit, 91 days has a more serious tone, princess principal doesn't sugarcoat it either. Princess principal has episodes interesting from start to finish and 91 days makes you want the next episode right away. 91 days had a heartbreaking twist and ending (well, at least, i didnt expect the twist) and I can't say anything about princess principal's ending yet, but it's already shocked me. Princess principal has badass cute girls so that takes away from the mood a little bit but somehow its just as mesmerising in it's own way. Both shows will keep you interested in what will happen with the respective wars and the characters. If you like either show you should definitely check the other out.

Both have the same dark-ish feel to them and distinct beautiful art.
Both are about clever plots created by exceptionally sharp characters and are quite deeper and complex than one might think at the beginning.
Both are loaded with action, drama and thrills must-see's.
While Monster's plot is much deeper and more developed and complex, 91 days' plot is developed to the best extent 12 episodes allow.

Op is very similar both because same group and the sadness in it
Similar the way that they have lost some of their loved ones
Dark

Both have something to do with the mafia, set outside Japan, have dark atmosphere.

Two animes rich in cold characters, serious and calculating, good action animes for adults. Both feature memorable action scenes and grayscale . They have a great worldbuilding and a maturity that is scarce in most of the current action shows.