poliwhirl, evee and some others
poliwhirl evolves into poliwrath with a water stone
The sun stone is an item similar to the thunder stone, water stone, fire stone and leaf stone it evolves two pokemon: Gloom and Sunkern.
There is no Pokemon in sinnoh that evolves by a water stone.
As of Pokemon Diamond/Pearl/Platinum, the Pokemon that evolve via Water Stone are: * Poliwhirl (evolves into Poliwrath) * Shellder (evolves into Cloyster) * Staryu (evolves into Starmie) * Eevee (evolves into Vaporeon) and * Lombre (evolves into Ludicolo)
evee
water stone
EEVEE evolves into VAPOREON by using a water stone
Poliwhirl evolves 2 ways: Either use a water stone on it or trade it while it holds the item king's rock.
The only one I know of is Eevee which evolves into vaporeon.
eevee and staryu
A Water Stone evolves a Poliwhirl, Shellder, Staryu, Eevee, and Lombre.
The Water Stone is in the Celadon Department Store, 4th Floor