This document contains a set of 15 fact cards on major groups of per- and polyfluoroalkyl substances (PFASs). The fact cards aim to provide non-expert stakeholders a quick initial glance into these groups of PFASs with some basic information on: (1) chemical identities, synthesis and inherent properties such as bioaccumulation and transformation, (2) historical and ongoing industrial practices and commercial uses of some major commercial products, (3) regulatory status, (4) examples of reported occurrences in the environment and humans, and (5) major knowledge gaps in terms of previous sections. The fact cards also provide references where interested readers may find additional information; note that due to the fast-moving nature of the science and knowledge on PFASs, the listed references are by no means complete. For information and practical guidance on the use of terminology in regard to PFASs, readers are referred to the OECD PFAS Terminology report.