Many people who collected Pokémon in Gen IV know that if you preorder DP (the DS copies) in Japan, you may get Dialga and Palkia figures made by Kaiyodo as bonus.
Little do they know that there are actually Clear (Dialga) and Pearl (Palkia) variants of those figures which can only be obtained by winning a lottery among Pokémon Daisuki Club members who preordered the games from Daisuki Select Shop. Only 250 each of these were ever released which made them extremely rare to find nowadays.
As for Platinum’s preorder bonus Giratina, there’s also the Metallic variant for Pokémon Daisuki Club members, although these are much easier to find than Dialga or Palkia as a total of 1000 figures were released.