You can continue to challenge the Elite Four for money and Exp. Also you can get additional badges (stickers).
Hall of Fame Sticker #1 Beat The Elite Four One Time
Hall of Fame Sticker #2 Beat The Elite Four Fourty Times
Hall of Fame Sticker #3 Beat The Elite Four One Hundred Times
Hall of Fame Sticker #4 Beat The Elite Four Two Hundred Times
you need to beat the elite four to go on the ss aqua
As soon as you beat the 8 Gyms of Johto, the Elite 4, the champion, and arrived in Fucsia City, then just go to the Pal Park where the safari zone was in Red, Blue, Green, Yellow, FireRed, and LeafGreen. It takes a while but its worth it.
well pretty much you can go to mount silver and battle red then you can get the kanto and hoenn starters
There's lots to do... Beat Elite Four. ***All this other stuff requires you to beat the Elite Four to do*** Catch swarm Pokemon (talk to Dawn's sister at her house in Sandgem town). Swarms happen every day, each is a random Pokemon exclusive to Pearl. Pokeradar Pokemon (Go back to Prof. Rowan's lab and receive from him). Use the pokeradar in a patch of grass and walk into a shimmering spot. Keep defeating the same species over again and usually an uncommon Pokemon will appear in a patch of grass. Go to the trophy garden south of Hearthome talk to owner and he will tell you a rare Pokemon is in his garden. (Random Pokemon each day). Beat Stark Mountain and Catch Heatran. Go back to Canalve City and Talk to the sailor's sick son, then talk to the sailor who runs the boat and go to Fullmoon island, get feather and see Cresselia, go back to boy to cure him. Cresselia will now appear at random times in a wild battle. Battle Tower: Win Battle Points earn TMs and Items. Pal Park: (Unsure as to whether Beating the Elite Four is required)
It does not beat
nothing
If you defeat the Elite Four Twice, you will have the opportunity to battle the Champion, Alder. He has mostly Level 72 to Level 75 Pokemon.
Then you beat them:)
you get laid
You just get legendary Pokemon I guess
route 7 after beating the elite 4
finish the nation pokedex
yes, you beat them ten times
Absolutely Nothing.
Nothing.
i think it happens when you beat the elite four
Nothing significant happens if you beat the Elite 4 three times in Pokemon Diamond, unless you include acquiring huge amounts of money and leveling up your Pokemon a very good amount.