Talented duo 【LambSoars】, composed of that and kakerine, are well known in the NND scene as amazing singers with an impressive résumé of original songs and Vocaloid covers. They have begun transitioning to YouTube with several anime and Japanese movie theme song covers. Amongst all their uploads, Haikyuu!! is one of the series with the most covers. The volleyball slice-of-life anime is also known for its energetic and upbeat opening and ending songs. Suffice to say, the covers below by 【LambSoars】are reason enough in convincing you to watch the anime, OR be a fan of the bands singing the original versions.
Too bad these covers are just TV sized (short) ones.