Angel Beats!, Ansatsu Kyoushitsu Recommendations
Both directed by Seiji Kishi. You will see a lot of similar comedic gags between the two series.
Group of misfit students who are in some special place or in special conditions. Both are comedies that try to be sentimental.
Both have teenagers wielding pistols, sniper rifles, and automatic weapons. Both have a very large cast of characters, almost all of which are students. The comedy style is, in my opinion, very close to that of Angel Beats. It isn't really trying to make you sad like Angel Beats does, but I really get the same feel off of both of them.
Both are about students and classrooms, in both the students try to get something done with plans (operations) and through action.
Both are set in a school
Both have a lot of comedy
Both can get you right in the kokoro (Well, AssClass's second season)
Both use a unique premise to liven up usually tropey school shenanigans, and both strike a good balance between comedic fun and emotionally stirring moments.