More than 53,500 gravestone records from around Ireland have been indexed by Ancestry as the Ireland: Graveyard Index 1600–2012 collection, one of its free to access (not even a need to register) 'Web Search' collections.
Index search results are linked to gravestone inscriptions on From-Ireland.net, a website managed by Dr Jane Lyons that's awash with Irish genealogy records and graveyard photos, all of them provided without charge.
In this particular collection, the graveyards are geographically spread over the island but by far the largest chunk are in counties Laois, Kilkenny and Kildare.
A second Web Search collection linking to From-Ireland.net is the Ireland, Trade Directory, 1931, which wil be of particular interest to those whose families were shopkeepers and merchants or provided local services. It's full of milliners, surgeons, photographers, bootmakers, publicans, hotels, brick manufacturers and so on.