Inventories are an essential part of many adventures. In fact, characters often start out with some items already occupying their pockets. However, that does not always make it useful; sometimes, the character will start with a crumpled piece of paper or an equally useless item.
Lance starts off with his watch in his inventory, and so far no one has tried to do anything with it, even when you ask a new character for the time and they say that you have a watch.
Stereotypical Protagonist begins with the Water(s) Prism, a magical artifact, in his inventory.
Another one in which the protagonist starts the adventure with an unexplained potion.
A little while after Masha is introduced, she checks her inventory and finds an actual crumpled piece of paper (which links to this very page). "Oh for crying out loud." However, she does find a use for it: knocking out a tantruming Cirno, who was flipping the fuck out.
The trope namer, this adventure features the main character starting off with nothing but a crumpled piece of paper.
The main character is thrown into a strange distorted world with naught but a candy bar.
Marek Larson, main character, awakens with a mysterious gray block and a very large stale cookie.
The main character starts with a generic potion; it may be worth noting that he also acquires a literal Crumpled Piece Of Paper later.