Note: This glitch only works offline in Local Co-Op on the same Switch. This glitch was performed on an unpatched version of the game. It may eventually get patched. To avoid not being able to use it, do not update the game online or delete any patches installed for the game on your Switch. This glitch require two players (two controllers). You must have two accounts, each with a character. Then, use the Resident Call app on your Nookphone to invite the other account/character. This glitch only works with placed items, and not items like bells or materials. Have player one place a desired item on the cardboard box or table. Have player two rotate the cardboard box/table, and then have player one grab the item while it is rotating (as the rotating player's arms are coming back towards the box/table). Player one will get the item and the item will still remain on the cardboard box/table. Repeat this process as many times as desired. Two good items to duplicate are the ACNH Switch and Tarantula, both of which sells for over 8,000 bells. You get the ACNH Switch and cardboard box in the mail on Day 1.
Successfully complete the indicated task to unlock the corresponding location:
Able Sisters: Buy at least 5,000 bells worth of clothing from Mabel at Nook's Cranny, then talk to her the third time she's in town.
Museum: Once you have Blathers in your town, donate 15 different specimens of fish, bugs, or fossils to him.
Nook's Cranny: After your first house upgrade, talk to Timmy. Collect and give him 30 pieces each of wood, hardwood, softwood, and iron nuggets.
Resident Services Building: After the three villagers you build houses for arrive, Tom Nook will announce the upgrade.
Successfully complete the indicated task to unlock the corresponding golden tool:
Golden Axe: Break 100 of any axe type.
Golden Net: Donate all bugs to the museum.
Golden Rod: Donate all fish to the museum.
Golden Shovel: Rescue Gulliver 30 times.
Golden Slingshot: Shoot down over 300 balloons to enable a gold balloon to spawn. Pop the gold balloon to get the recipe inside.
Golden Watering Can: Get a five star Island Evaluation.
Each day, one randomly chosen rock in your town will produce bells if you hit it with your shovel. You can hit it up to eight times, resulting in successively larger payouts per hit. Make sure to dig holes behind your character beforehand so they do not get knocked backward upon impact.
When you see a glowing gold crack in the ground, you will dig up a bag of bells. If you bury a bag of bells of any amount in the glowing hole, you will grow a money tree with three bags of bells on it when it fully grows that are each equal to the amount planted. Note: If you plant a bag with more than 10,000 bells in it, there is a chance the bags on the tree will only have 10,000 bells in them.
Once you begin crafting a recipe and the materials are being tossed around, repeatedly press A to speed up the process.
Each day there are two trees on your island that will give you a piece of furniture if you shake them. There is at least one tree at each mystery island that will drop furniture as well. Note: The furniture only falls if you shake the tree rather than hitting it with an axe, and the fruit trees do not drop furniture.
If you see a shooting star, tilt the camera up while not holding anything, and quickly press A to wish on it. The fragments will then wash upon the shore the next day.