This document discusses making ontologies FAIR (Findable, Accessible, Interoperable, Reusable) through the use of ontology repositories. It provides examples of existing repositories like NCBO BioPortal and how they help standardize ontologies and make them more discoverable and reusable. The document also describes related projects that are reusing NCBO's technology like AgroPortal for agricultural ontologies and SIFR for French biomedical ontologies and terminologies. Key challenges discussed are scaling repositories to many domains and large numbers of ontologies while maintaining features and curation.