My Hero Academia: Training of the Dead
A Action and School series worth adding to your list.
Returning from their internships, the students of Class 1-A are immediately thrown into more training by their homeroom teacher, Shouta Aizawa. For this exercise, the class will be joining four students from Isamu Academy High School to compete in a survival game. Split up into groups of four, students must either eliminate each other or stay hidden until time runs out to win. The training also acts as a reunion between Tsuyu Asui and her friend from middle school, Habuko Mongoose. However, not all the students from Isamu are friendly—Katsuki Bakugou almost instantly picks a fight with Romero Fujimi. The conflict between the two leads Romero to angrily release his Quirk, a gas which zombifies anyone it comes in contact with. How will the remaining students deal with the situation after most of the people around them turn into zombies?
Plot summary from MyAnimeList. Data and images via Jikan API.