In the context of unprecedented global change, there is growing interest in the role of various agents of change in shaping and transforming social-ecological systems (SES) toward more just and sustainable futures. However, the diversity of terms used to describe these change agents prompts the question of whether these terms represent distinct functional roles and if and how they overlap. This article aims to clarify the meaning of 10 terms related to agents who catalyze and guide SES processes that aim to advance change: boundary spanner, change agent, gatekeeper, information broker, institutional entrepreneur, knowledge broker, networker, policy entrepreneur, social innovator, and visionary or visionary leader. Using the bibliographic database Scopus, we conducted a rapid review of the SES literature to determine how each term is defined and used, the function and strategies of each type of agent, the contextual factors enabling their actions, and their overall contribution to broader social-ecological processes. Our findings suggest that agents can be divided into two broad clusters based on their functional roles. One cluster consists of actors aiming to facilitate information flows, and the other of those who aim to instigate specific changes through their activities. In some instances, agents may perform two or more roles simultaneously implying that they may target more than one function. We found that the actions of these agents shape and are shaped by a range of contextual factors, particularly structural and institutional processes. Although this study helps to provide conceptual clarity to the different terms and their main functional roles, more research is needed to better understand their roles at different points in transformation processes and the contexts that mediate their behavior and strategies.