I found two one shots that both seem to have been early iterations of Haikyuu!! The core idea of Hinata being very athletic, but not able to hit the ball consistently is there in both of them. But in one, Kageyama recruits a non-sportsminded Hinata who has low drive and self-esteem issues. In the other, Hinata does have the familiar drive to practice as hard as it takes to be allowed to be on the team. In both of them, they come to an epiphany which leads to Kageyama setting it so Hinata will hit it without even looking (though the way they arrive at the epiphany differs in the two versions). I don't think the main series got into that idea until a few chapters into the story. In one of the versions, we see Kageyama learning some lessons on how to be a better setter. Both versions have Kageyama already be an accepted part of the Karasuno team and struggling to break through the defense during a practice game, so the rookie Hinata is thrown in (in one version, Kageyama suggests this substitition femself and in the other, fe thinks it's a bad idea). Tanaka and Daichi makes appearances in both versions and in one of them Tsukishima appears as well, though as a second-year and without feir trademark wiseass apathy. Neither version includes the middle school clash or Hinata's feelings at being on the same team as the person fe saw as feir rival. Honestly, that premise was probably what hooked my attention for the early chapters of the main series until I got to know the characters better. And, just from these one shots, I don't think these characters are quite as endearing or interesting as they end up being. One of the one shots focuses on the idea that only the strong can have fun during matches and the other focuses on the idea that a team works together with a series of connections to keep the ball alive, with both of those ideas becoming recurring themes in the main series as well.