What types do you associate most heavily with each region?
For kanto i think of poison and water because of the 150 pokemon about 1/3 are poison and 1/5 are water and also my fave water types are from here

For Johto I think mainly of normal types because of all the single stage normal type pokemons, and honestly because the lack of any other type being extremely present

For Hoenn i think of the obvious water types

For sinnoh I think of steel and ice, even though not many ice types were introduced. Steel because of lucario and wormadam and bronzor and bastiodon which are all pretty unique and cool steel type pokemon, esp for a smaller sized dex

For unova i think of dark types just because no other types really stand out to me

for Kalos fairy and dragon for obvous regions, and for alola just from the leaked dex I'd say grass types.