1.Legenderies I know the trading system might be messed up that's why I thought u should be able to catch one legendary in each region then all the other legendries get turned off
2.Sinnoh region it was before soul silver so the Pokemon would still be able to follow u and the sinnoh region is one of my favorite
3.events where u can get a shiny like maybe for Christmas u can participate in a event where u can get a shiny
Those r my suggestions if u agree or disagree comment below