Carbink and Diancie not being related also confused me.
Oh and Remoraid and Octillery is a classic one for sure.
GTM posted...
I know it's not what you mean by "pokemon that are related", it makes me think of
A) version exclusive or limited pairs, like Ekans and Sandshrew, I forget for example right now what Meowth pairs with in rby but right now I re-remembered it's Mankey. Or Oranguru and Passimian is one.
B) Pokedex entries with other pokemon. Raichu knocking over a Copperajah always makes me go "oh yeah that's a thing, they have a relation" or Onix disturbing Diglett tunnels and such
I mean, sure, I was thinking of evolution lines, but this is also an interesting aspect of Pokemon. Also I like it when new Pokemon has an older Pokemon in its Dex entry, makes the world feel more interconnected.