A fully-functional unused feature allows you to name the player's mother in Pokémon Gold and Silver. This feature was used in the Spaceworld '97 demo's dummied-out story mode, where Silver offers you a choice between おかあさん (お母さん Mother), ママ (Mama), かあちゃん (母ちゃん Mommy), or choosing your own name. The name itself can be displayed in text via byte 49. The mother's name is initialized to MOM when RAM is initialized at boot.
Curiously, during the DUDE's Pokémon-catching tutorial, the player's name is copied over to the same location in RAM where the mother's name is stored. This suggests that by the time the tutorial was created, the naming mechanism was either already unused or deferred until the tutorial was no longer accessible.