The trio in ruby, sapphire, emerald, is Regice, Registeel and Regirock. In Pearl, Diamond and Platinum Regigigas is released to those who trade the 1st 3 regis into their P/D/Pt.
Below I have added a link on how to get them.
You can get three rare candies in Pokemon ruby sapphire and emerald
...and?
Solrock is not such a rare Pokemon but you can only get them in ruby/emerald
You catch them. Or trade for them.
n e where
Groudon is rare and you get him just by following the story line. The only other "rare" Pokemon I'm aware of in Ruby would be Relicanth, a rock/water type fish Pokemon that can be found underwater.
Rare Pokemon come randomly when you're in the grass or cave.
use the itemfinder
There are a few rare Pokemon you can get in the safari zone they are pinsir, wobuffet and girafarig.
Pokemon ruby sapphire and emerald
i think there's none
OK the rare Pokemon are groundon, i think there's the 3 regies regirock,regiice,registeel. And you can also get this strong Pokemon named milotic. But you need to evolve it from feebas though. hoped this helped!:)