Route 17: Four squares east and two squares north of the northernmost Cue Ball, in the patch of grass (hidden)
Cerulean City: One square south and three squares west of the northeast corner of the backyard of the Gym Badge man's house (hidden)
Mt. Moon: 1F, near the southeast corner of the floor
S.S Anne: 2F, in the fourth room from the left
Rocket Hideout: B3F, on the east side of the spin tile maze
Pokemon Tower: 6F, in the west area of the floor
Silph Co.: 10F, in the southwest room
Fuchsia City: Inside the Safari Zone Warden's house (requires Strength)
Power Plant: In the northeast area of the facility
Pokemon Mansion: B1F, in the northern area of the floor and B1F, in the northwest corner of the area with the Secret Key (hidden)
Victory Road: In the north area of the first floor
Cerulean Cave: 1F, on a rock on the plateau east of the Full Restore (hidden)
There are two very fast methods to get Rare Candies in Sword and Shield. One of them is to continuously do 5 star Max raid battles. A lot, (not all,) give out multiple Rare Candies, and each raid den only takes 2-3 minutes.
The faster is long and a little complicated if your not familiar with date skipping in SwSh. This requires six gym badges.
Go to the Vs. tab in your menu, go to Battle Stadium, and hit Casual Battles. Pick either Single or Double it doesn't matter. Select your party and wait for an opponent.
Once an opponent has been found, select your Pokemon to battle, (it does not matter who you pick at all,) and ready up.
Once the battle is starting, as soon as you see your and your opponent's league cards, hold the home button on your controller, and hit airplane mode. (Note: you have to undock your switch to do this.) A error message will appear on your Pokemon battle. When this happens do not hit "Close" or "Details." Hold the home button again and turn airplane mode back off. This will get rid of the error message, and then the battle will end near instantly. You may have to back out of the battle yourself, (just hit run.)
Now your game is in a temporarily glitched state. Now, everytime you go to the Home Menu, go to System Settings, scroll down to System, go to Date and Time, and then change the date, the day will reset in your game. Meaning all hidden items, (sparkly items on the ground) will be reset.
Make your way to the island in the middle of Lake Axwell that has a Haxorus on it. If you go to the far side of the island, inbetween the patch of grass and the water, there should be a sparkle on the ground. This is a Rare Candy. Pick it up. The farming has begun.
Fly to East Lake Axwell, (the spot right underneath Motostoke,) and then change the date of your Switch. Once you enter back into the game, you should notice a small flicker, and then the weather changing. This has reset the Rare Candy you just obtained. Make your way back over to the island, pick up the Rare Candy, and repeat this step until you are satisfied.
I do not know why you can't be on the island when you reset the Rare Candy, but it will not work. Make sure not to close your game during this process, because that will end the glitch.
Hope I could help
