Apparently the Met has open access pictures of samplers with designs that are basically blackwork! I didn't find them last time I searched because they're under "double running stitch" rather than "blackwork" specifically.
https://www.metmuseum.org/art/collection/search/221650
https://www.metmuseum.org/art/collection/search/231822
https://www.metmuseum.org/art/collection/search/219509