Mushroom

The mushroom exists in 4 Zelda games, A Link to the Past, Link's Awakening, Ocarina of Time, and Oracle of Seasons. In ALttP and LA the mushroom is given to the witch for magic powder. In OoT it's merely a trading item to get some magic powder for a lost man. In OoS, it is an item in the Trading Game, a quest for the L-2 Noble Sword.