Everything. Kill it with EVERYTHING.
Could be that her talent is in the jewellery business. Maybe she made that tiara herself. It's not too far off from Rarity's cutie mark story.
Could be, though it's not really a talent. Maybe she makes silverware? Or collects spoons?
There was actually a fic a while back where Silver got spoon-fed by a servant. That was it. That was the entire fic.