>>29345333Instead follow the rule that you can use two of the same type on a team, so long as they're each dual-types with different type combinations. For example, you could use Lanturn and Relicanth on a team, but not Wishiwashi and Pyukumuku (same type combination and both are monotype,) Gyarados and Mantine (same type combination,) or Seaking and Starmie (monotype is "contained in" the dual-type.)
I occasionally try to follow this rule, but I'll make an exception for my first playthrough of each gen. My first Alola run is undoubtedly gonna have a fuckton of water-types in it.