Here are my favorite picks for similar anime to Prison School. Keep in mind the list is in no particular order. Enjoy the recommendations!
Seven teenagers in 1955 have to learn to live together in the same hold in the reformatory of Shio. Confined in a hall where suffering and humiliation are daily, they are waiting for a ray of hope in a dark, incarcerating world. The story follows their life together and how they move on afterwards.
The Amanto, aliens from outer space, have invaded Earth and taken over feudal Japan. As a result, a prohibition on swords has been established, and the samurai of Japan are treated with disregard as a consequence.
However one man, Gintoki Sakata, still possesses the heart of the samurai, although from his love of sweets and work as a yorozuya, one might not expect it. Accompanying him in his jack-of-all-trades line of work are Shinpachi Shimura, a boy with glasses and a strong heart, Kagura with her umbrella and seemingly bottomless stomach, as well as Sadaharu, their oversized pet dog. Of course, these odd jobs are not always simple, as they frequently have run-ins with the police, ragtag rebels, and assassins, oftentimes leading to humorous but unfortunate consequences.
Who said life as an errand boy was easy? [Written by MAL Rewrite]
Akutabe, a detective, summons devils to solve the troubles of his clients. One day, a low class devil Azazel Atsushi is summoned by Akutabe and is used harshly by him and his assistant Rinko Sakuma.
Ganta Igarashi has been convicted of a crime that he hasn’t committed, and sent to a new, privately owned and operated prison, where the inmates are the main attraction in a modern day twist to the gladiatorial coliseums of ancient times. Throw in a healthy dose of weird little girl, some new-found super powers, and a little conspiracy theory, and you have Deadman Wonderland.
In the future, Japan is a wasteland. In the Great Kanto Desert, scattered humans eke out a living in the hot sand. Among them, a short-statured man they call “Sunabozu” makes a living as a bounty hunter. Like a demon of the sand, he seems unbeatable. Yet, like all men, he has a particular weakness for the opposite sex…
References: MyAnimeList, Wiki, ANN