There are several studies analysing different, individual protein sources for nutrition from diverse plants, and groups of plants pertaining to underutilised vegetal sources, microalgae and insects. This review deals with the economic facts and trends observed within the entire supply chain palette of proteins globally, starting with protein sources, followed by market situation and future trend analysis, including nutritional quality comparison of different proteins derived from diverse resources. Since there is a lack of such an overview, the review provides a comprehensive “state-of-the-art” of the scientific and technological evidence related to protein-rich vegetal and non-vegetal sources and the pathways of their valorisation, as well as highlights trends in protein food security and consumption for the next decades.