Eighteenth Century Collections Online provides access to facsimile page images and full text of works published in the British Isles (plus some from North America) during the 18th century. The collection includes books, pamphlets, and broadsides. Users can search within texts keyword and download them as PDFs.
For a full list of databases pertaining to philosophy, including some that are highly specialized, please consult the page Databases A-Z: Philosophy on the library's site.