This session aimed to showcase the ecosystem of thematic marketplaces for the EOSC and their role as aggregators. EOSChub kickstarted the session by painting the landscape of science discovery marketplaces. All 5 EOSC cluster projects highlighted how each of their value propositions relate to the EOSC portal based on key lines of activities that cluster projects for aggregation. Such as UX design & development, content & sources, curation & governance. We’ll discover the similarities and differences in these approaches, share best practices and identify possibilities for future collaborations. Agenda: The EOSC ecosystem of open science marketplaces - from EOSC-hub to EOSC Future - Owen Appleton (EGI, EOSC-hub) Discussion Thematic Discovery Marketplaces for the European Open Science Cloud SSHOC: SSH Open Marketplace - Frank Fischer (DARIAH) EOSC-Life: Registries for software and workflows - Carole Goble (University of Manchester) ESCAPE: software and service repository - Kay Graf (Friedrich-Alexander University Erlangen-Nuremberg, ECAP) PANOSC: Federated Catalog service - Tobias Richter (European Spallation Source) ENVRI-FAIR Data/service catalogue- Andreas Petzold (Forschungszentrum Jülich GMBH) Conclusions - Owen Appleton (EGI, EOSC Enhance)