It’s always exciting when a new design becomes a bestseller. In a few special cases, it means that the manufacturer will invite the designer to turn one great product into a whole family of products. Whether they are reimagining a design with new finishes, or creating an entirely new piece of furniture, designers are always eager to build upon original designs and earn the status of having birthed “a collection.” This week, we present five brand new products from Patrick Norguet, GamFratesi, Vincent Van Duysen, El Schmid, Ilkka Suppanen and Raffaella Mangiarotti that are the second, third, or even fourth expansion of a bestselling design.