3D printing is a revolutionary technology for the consumer and industrial markets. As the technology for 3D printing has expanded, the need for multi-materials that support fused deposition modeling and other forms of additive manufacturing is increasing. 3D printing filaments infused with carbon nanotubes and graphene are now commercially available, with the promise of producing conductive composites. This chapter explores some of the research, products, and challenges involved in bringing the next generation of functional printing materials to the consumer market.