Designer are LEGO sets that come with an assortment of System pieces made for creating and designing your own models with, in the tradition of Basic and FreeStyle. They include Idea Booklets to help with model inspiration, and come with no instruction booklets. Designer sets were introduced in 2003 and their content as well as the philosophy of stirring creativity by just providing LEGO pieces and a design outline overlapped with Creator, into which Designer was eventually merged in 2006.
A subtheme of Designer was X-Pods which ran from 2004 to 2006.
Designer sets can usually be distinguished by having one main model to sell with, two other models with full instructions, and inspiration for other models. They are favorites for children, teens, and adults who enjoy LEGO more for building and designing rather than playing with and fantasizing.