You can get a fisherman's phone number and then someday he'll call you and make you come in where the fisherman battled you and maybe he might give you a water stone.
U buy it at goldenrod dept store
its in the edge of the stone
Use rocksmash
you can migrate it from firered and get one then get the egg of it hatch it and done to evolve it by water stone or
hard stone can be found at dark cave
You require a Water Stone for it to evolve
you need to get a sun stone and use it on gloom
In order of how he wants to see them (based on Heart Gold and Soul Silver): Gold/Heart Gold: Oddish - Leaf Stone Growlithe - Fire Stone Pichu - Thunderstone Jigglypuff - Everstone Marill - Water Stone Silver/Soul Silver: Lickitung - Everstone Oddish - Leaf Stone Staryu - Water Stone Vulpix - Fire Stone Pichu - Thunderstone
A heart of gold itself is an expression relating to someone kind. "They have a heart of gold".
Poliwhirl, Shellder, Staryu, Eevee, and Lombre.
use a water stone o evole it
Staru and Poliwhirl are the only ones I can think of.