You don't get the magna stone from buck in Pokemon platinum.
It does not evolve with a dusk stone in Pokemon Platinum
The Pokemon that can use oval stone in Pokemon platinum is Happiny. It is the pre evolve form of chansey. Mostly every chansy you catch have a oval stone.
a grass Pokemon
eevee
Happiny evolves into Chansey with an Oval Stone.
underground
underground
toolmon obviously
i think eevee
vulpix to ninetales growlith to arcanine evee to flareon
you can find a thunder stone by checking the UNDERGROUND