I think they're both unreleased MM items but they're still in the list.

Item not found: beanie meanies - how to bag beans Beanie Meanies - How to Bag Beans

Item not found: chess strategy cards Chess Strategy Cards

they were originally going to be part of Mysterious Melody but MM didn't happen so they were changed to staff rarity so as not to interfere with collections being able to be completed or confuse people :)

well they're still in the book collection list. Hopefully they'll get taken out one day.