There is relatively little on ocean downscaling within C3S. Probably the most relevant dataset is this one https://cds.climate.copernicus.eu/cdsapp#!/dataset/sis-fisheries-ocean-fronts?tab=form generated by Plymouth Marine Laboratories for one contract on ocean impact. Med-CORDEX provides some high-resolution ocean projections for the Mediterranean Sea (www.medcordex.eu), CORDEX-Arctic for the Arctic Ocean and Baltic Earth for the Baltic Ocean.