Heres the gold or silver tools and how to get them:

Golden Axe: Throw an axe into the town fountain to randomly turn it golden.
Golden Fishing Rod: Catch every species of fish.
Golden Net: Catch every species of insect.
Golden Shovel: Bury a normal shovel then dig it up four days later.
Golden Slingshot: Knock down eight balloons to have a random chance of obtaining it from a balloon.
Golden Watering Can: Earn a "Perfect" town rating for fifteen days, then talk to Pelly at Town Hall.
Silver Axe: Throw an axe into the town fountain.
Silver Fishing Rod: Purchase from Tom Nook's store.
Silver Net: Purchase from Tom Nook's store.
Silver Shovel: Obtain from Resetti's Surveillance Center in the city.
Silver Slingshot: Purchase from Tom Nook's store.
Silver Watering Can: Purchase fifty bags of seeds from Tom Nook's store.
Hope this helps