Graphene sheets have outstanding electrical, thermal, and mechanical properties. Furthermore, owing to the
abundance of naturally existing graphite as the source material for graphene, it is considered an ideal reinforcing
component to modify the properties of matrix, compared with other carbon nanofillers. This review will summarize the
development of graphene/polymer composites, graphene/nanoparticle composites and graphene/carbon-based materials
(nanotubes, fullerenes) composites in recent years, including the fabrication of nanocomposites, mechanical properties and
electrical properties, thermal conductivity and thermal stability. The synergy of graphene with other types of carbon
nanofillers used as hybrid reinforcing systems shows great potential and could significantly broaden the application of
graphene. The relevant research will also be included in this review.