Wikidata has a property for IIIF Manifests called IIIF Manifest (P6108). This allows queries to be written that will retrieve manifests if they match other Wikidata properties. Example queries are below:

• List of all IIIF Manifests on Wikidata by Collection
• IIIF manifests of works by Turner
• IIIF manifests for self-portrait paintings
• IIIF manifests of illuminated manuscripts