well actually i dont think anyone has fully completed the game (without cheats that is) but know what you mean...
there is always the shinys to get, and basically you have to battle other people, and work out battle strategies so your the best, but i can tell you nothing there
you have completed the unown, got all 26 and opened the doors at the end of the puzzle chambers...
there are no mysterious pokemon that i know of...
secret items are all over the place, but im sure you woulda found most of them...
the day people that come one person for each day and they give you items...
gotten celebi?
Join this site...http://s14.invisionfree.com/ChaoticRoleplayRealm/index.php?
and this one...http://gameknot.com/?rfr=diezombie...when you sign up the second one, where it says referals by, type in diezombie