Gold plating can be a good solution if the acidity of your skin is very corrosive to silver. It will protect your keys nicely and is resistant to discoloration. Gold plating can also be applied at specific spots, which are exposed to higher wear, so that the rest of the instrument remains silver-plated. This is a nice solution for players who need the protection but dont like the gold image.
Gold plating is available in different colors. Yellow gold, red gold, rose gold. This is achived by adding other metals, like copper, to the gold plating.
Other options could be palladium or rhodium, but both are very expensive