This atypical item listing is for anything RPG-related which is not an actual game product. For example, RPG-related pins or buttons of an interesting or curious nature, GenCon or other convention flyers or brochures, TSR Product Catalog covers, etc.
Note that items such as convention catalogs may be listed separately only if they contain actual gaming materials, such as an adventure scenario. Such catalogs are, overall, fairly rare.
For merchandise of a more general gaming nature, or more related to board games, see the similar Miscellaneous Game Merchandise.