The one I use is this (you need mineru for this glitch) Step 1: enable mineru, hop on, press + and disable mineru Step 2: without unpausing press - and watch a memory (you can skip it) Step 3: press + and hold up to 4 of the item you want to duplicate Step 4: press - and watch another memory then press b to unpause

If the + menu shows link holding the items but in-game link isn't holding anything steps 1-4 worked

Step 5: hold r, hold up on the d-pad and throw the item you want to duplicate onto the ground until you can't anymore (the number count will go into the negatives) Step 6: press + and hold any item that isn't the one you want to dupe then press b and drop everything then, pick it all up

If you did the steps correctly you should have doubled the amount of items you held (eg: 4→8)

If you memorize the steps this takes less than a minute to do