I have found a few useful links of headstones in Devon
- Devon Headstones - an alphabetical list of individuals and the inscriptions of the photographed headstones. Pictures can be ordered by contacting the site owner here.
- Of the Parish, a collection of photographs of from the City of Plymouth. Headstone details and small, watermarked images are available online, but prints can be purchased too.
- The Gravestone Photographic Resources project, specifically the section on Devon.
- Tollhouse Allan's Devon Gravestone Set on Flickr, with about 100 pictures, but in no particular order.
Finally, searches for phrases like "Devon Headstone/Tombstone/Gravestone..." will turn up large numbers of sites with small sets of photos that are of interest to the researcher who put them up. Don't forget to search by placename as well.