Since the launch of Blue-Cloud, the project has proactively worked on establishing strong partnerships between a variety of actors, aiming to create long-lasting relationships both for attaining the Blue-Cloud's long-term objectives and for contributing to shaping the strategic Roadmap to 2030. Blue-Cloud has established synergies in the Open Science, Blue Economy and Marine Research fields as the team believes that through collaboration and cooperation with initiatives operating in the same field, the value of Blue Cloud services increases. As output of this effort to cluster with related projects and initiatives in Europe and Beyond, this first release of the Blue-Cloud Factsheets for cluster projects and other core initiatives presents an overview of all the projects and infrastructures Blue-Cloud has established synergies with in the first year and a half from its launch (M18). The collaborations span from data integration to joint communication events. Overall, the synergies established have been classified around the main assets of the Blue-Cloud infrastructure: Data Discovery and Access Service, Cyber Infrastructure and Virtual Research Environment, and Demonstrators, plus a categories for those initiatives looking forward to contribute to the BlueCloud Roadmap. So far Blue-Cloud has established connections with 32 projects and organisations and has started concrete collaboration with 21, greatly surpassing the KPI for M36 (10). The dialogues represent the ground layer for successful collaborations to be pursued in the next months, leveraging on the public availability of the Bluer-Cloud resources, namely the demonstrators and their VREs (launched for public use in March 2021), the Blue-Cloud Discovery and Access services (to be ready in May 2021) and last but not least the unprecedented wealth of data resources of Blue-Cloud. This document represents a first release of the Blue-Cloud fact sheets for cluster projects and other core initiatives. * Section 1 presents the approach adopted and an overview of the synergies established in the framework of Blue-Cloud main assets. * Section 2 lists the Factsheets for cluster projects and other initiatives, grouped by e-Infrastructures (2.1), Blue Data infrastructures (2.2) and other projects and initiatives (2.3). A second release of this report (D6.6) will be produced at the end of the project (M35).