Golden Watering Can - Keep the environment perfect for 14 days in a row. Pelly or Phyllis will reward you with the golden can.
Golden Shovel - Bury a regular shovel in the ground, and then dig it up a full day later. It will then be golden.
Golden Slingshot - Shoot 15 items out of the sky, then you get it if you shoot it down.
Golden Bug Net - Catch every type of bug once.
Golden Fishing Rod - Catch every type of fish once.
Nooks Cranny (lvl 1) - Available from start
Nook 'n' Go (lvl 2) - Spend 25000 bells
Nookway (lvl 3) - Spend 65000 bells
Nookingtons (final upgrade) - Spend 240000 bells and have a friend shop at the store
But if you've got the Country Guitar, give it to K.K. Slider to get K.K.'s Pic
And if you got the Red Vase, give it to Crazy Redd in exchange for the Safe. Give the safe to Tom Nook for the Tom Nook Pic.
Sparklers
Roman Candles