The circular economy has been heralded as a potential driver for sustainable development by business, academia, and policymakers. In a future circular economy, new business models are needed that slow, close and narrow resource loops to address key resource and climate challenges. After a phase of excitement and inspiration, an operationalization phase needs to start to ensure the best possible implementation and transition towards a circular economy. This operationalization phase will involve the development of products, processes and business models that significantly lower the negative impact on the environment, reduce waste and resource pressures and, rather, create a positive impact on society and environment. This paper focuses on the circular business model lens as a comprehensive way of addressing business innovation. Within this evolving circular economy operationalization phase, several tools, approaches and methods are emerging that could support circular business model innovation. This paper seeks to create a comprehensive tools overview through a literature and practice review. It provides structure to the emerging range of tools, methods and approaches, and, based on this, a guideline for future tool development. Finally, it gives an overview of opportunities and gaps as well as a future agenda for research and practice.