This article outlines the fundamental challenges of democratically planned economies and categorises proposed models into six groups, each of which approaches planning and coordination at different levels of authority and between myriad economic units in a particular way, taking into account efficiency as well as democratic principles and environmental and social sustainability. Through a classification system based on decision-making authority and mediation mechanisms, the article provides a framework for understanding and comparing these models. By examining their different approaches, it offers insights into the complexities and potential paths of democratically planned economies in the 21st century.