If you complete the national pokedex, go to visit Prof. Oak and he will give you a ticket to a place called foggy valley. You have to get a ticket because it is also an island.
Chat with our AI personalities
nothng happens
Complete the Unova pokedex (after that coplete the national pokedex)
nothing.
Pokemon 386 completeYou get a diploma from a gamefreak guy located in Celadon City.
Oak just shows up out of nowhere that's it.