The remarkable mechanical, chemical, and physical characteristics exhibited by metallic glasses (MGs), arising from their disordered atomic arrangement, present substantial application prospects in the aerospace industry, consumer electronics, biomedical implants and devices, sporting goods, etc. However, the brittleness introduced by highly localized shear bands poses a limitation to broader applications. A promising approach to overcome this limitation involves the development of metallic glass composites (MGCs) via introducing a second phase (or multiple phases) to impede shear band propagation, effectively enhancing MGs' plasticity. This review aims to provide a comprehensive overview of the advancements in methods and mechanisms for improving the plasticity of MGCs. It is divided into two main sections: one detailing the impact of in-situ second phases, such as glassy, quasi-crystal, and crystalline phases (nano- and micro-particles, dendrites, B2 phases, ceramic phases, etc.), on the plasticity of MGCs at different scales. The other section explores the influence of ex-situ second phases on the plasticity of MGCs, encompassing particles, fibers, interpenetrating phases, as well as laminated structures like nano-laminated architecture, coatings, and shrink-fit metal sleeves. Additionally, the review outlines challenges and future prospects in the quest for high plasticity MGCs at room temperature.