Some pokemons you can only get by gameshark or AR.They are
Mew
Celebi
Lati@s that you didn't chose
Deoxis
Jirachi
Ho-ho you can get trading from pkmn colosseum,lugia by trading from xd,the bird trio(zapdos,moltres,articuno) by trading from fire red/leaf green,the same for the dogs trio(raikou,suicune or entei,depends from you're starter).Mewtwo is in the same way. Note:There was a way of getting celebi at the japanese version of pkmn colosseum,but I don't exactly how.
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