These codes are for the USA version of SM64, and have been verified to work with SM64GSW correctly. Any additional details are found below, and the original code source has been linked to for credit.
Turn this code on before the tittle screen appears. Go to Hazy Haze Cave and look around the whole course for a giant eye ball that you get a star from when it’s defeated.
Turn this code on before the title screen appears. Go to any course that has the small breakable boxes and they will be replaced as vanish cap blocks.
Turn this code on before the title screen appears. Go to any course that has the small bouncing boxes and they will be replaced with chunkyas. NOTE: This code works, but the chuckyas are invisible.
Turn this code on before the title screen appears. Go to Bob-Omb Battlefield and go where the water bomb drop objects usually be and you should find king bob-ombs. NOTE: This code works, but the king bob-ombs are invisible.
Turn this code on before the title screen appears. Go to Jolly Roger Bay or Dire Dire Docks and the seaweed under the water will be replaced with water koopa shells that you can pick up and ride underwater.