Pokemon Pearl DS Help, After the Elite 4?

The Pokemon League is the E4 lol... Now that you've defeated them complete the Pokedex and get a National one... then you can get on a Ferry off to The Battle Zone then you can do these things and much more; Complete a 500 odd Pokedex, Complete the 100 winning streak at the battle tower, go to the Pal Park and transmit Pokemon from Sapphire, Fire Red, Emerald, Ruby, etc... Get a full - 6 Pokemon team all to level 100 and fight other real trainers over Pokemon Wi-Fi, Get all the Pokemon Trainer Stars on you trainer cards and much, much more!!! and also, If you want even more detailed answers to questions like this and harder/easier ones then visit one of these two websites that are located in My Resouces links.

Your gonna have to see all 150 Sinnoh Pokemon to gain the National Dex. First, you might have to see 3 legendaries which are at the 3 lakes.

I'm pretty sure you haven't seen a unown so you might wanna do that.

There are unowns in the ruins right of Solaceon town. Once, you see all 150 Pokemon you are allowed to travel to Resort and Survival Area.

the elite 4 is the pokemon league. after the pokemon league, if you have seen all the pokemon in the pokedex you can get the national pokedex. you can also go to the battle tower.

the elite 4 and the champion are the pokemon league. now you can go catch legendary pokemon!

I would first go back to where ur journey started. To your home. Then there should be some note for you there, on the table. That is what happened to me.