Chekov's Spell -- This spell has a two-fold effect. The first is to make the target item almost-unnoticeable to anyone not specifically looking for it. The second is that someone who has seen the item will remember it when they encounter a situation that would be perfectly solved by use of said item.
According to the Journals of Lord Goidol, the people of the Southern Cities wear heavy coats all the year round, despite the stifling tropical heat. They claim that to do otherwise angers the gods, and it is true that visitors who refuse to don the local garb are often struck down with a paralytic fever.