dragon ball gt
The third Dragon Ball anime series originally created as a direct sequel to Dragon Ball Z. Unlike the other series, the story is completely original and mostly lacks involvement from Toriyama Akira besides some character designs and concept art. Super Saiyan 4 would be introduced in this series.
Due to the anime's relative unpopularity in Japan, it aired for only two years between 1996-97 before being cancelled. GT would be considered non-canon with Dragon Ball's revival in 2013 and the later airing of Dragon Ball Super. Elements introduced by GT would later be picked up by the Dragon Ball video games, notably Dragon Ball Heroes, keeping exposure to the series well after its cancellation.