I've never watched Haikuyuu but I have watched and read Bluelock several times. I would say Ace of Diamond has a similarish concept to Bluelock. In it, the mc goes to a very intense baseball highschool and spends almost all day training. While the environment is not as toxic and intense as Bluelock, it still has a lot of rivalries and pressure situations, with the mc also relatively isolated from the real world. The relationships between characters is similarish to Bluelock, in the sense that even between friends, they also compete amongst their team mates. It is overall a very good manga (I've never seen the anime) with a lot of good characters and interesting plot choices (even for someone who knows nothing about baseball).
