>Dragon Ball
A mandatory prequel, necessary to discover Goku's early life & adventures.
>Dragon Ball Z
The loved-by-the-mass main series, turned by Toriyama into pure action that naturally attracted the lowest IQ people into the franchise.
>Dragon Ball Super
A terrible, non-canon continuation of Z, with a boring grey ayy.
>Dragon Ball GT
An excellent continuation of Z, free of Toriyama and made by people who understood what Dragon Ball was about.