If you remember having added an item on the list, sometimes this life, but you cannot seem to find it – it’s most probably long deleted, anyway – you can go to My Items (three dots menu, top right of screen) and reuse it from the list.
“My Items” is pretty much a history of every item you’ve ever added to your lists. In case you wish to redeem an item from this list, you can do so by checking the checkbox next to it and then tapping “Add to the list” down the bottom of the screen. You can also do this for multiple items at once, just check multiple checkboxes.
You get a chance to edit the item before adding it (or update the details on a very old entry, such as price and quantity): tap and hold the item then do all necessary changes. You can even assign it a barcode, for future reference and speedier use (check this FAQ on Barcodes for details on how to make the most of it) 😊