The information on Irish wills and probate records as genealogical sources has been significantly updated and improved.
An increasing number of will abstracts is now available, partly thanks to a new release of data on Ireland's Virtual Record Treasury. Notable additions include some of the Groves collection of will abstracts, those made by Rev Canon Leslie (probably CoI priests), those made by Rev Canon William Carrigan (Catholic wills), some original prerogative court wills, some abstracts made by Henry Swanzy (although unfortunately not his main collection) and some private gifts to the National Archives of Ireland. One hopes that the Record Treasury will contine to add more of these.
I have also discovered more about what is available elsewhere, particularly in the Miscellaneous Testamentary records held by the National Archives of Ireland and available on FamilySearch.
Both Ancestry and FindmyPast have also added to their collections. Ancestry has added the Betham, Crossle and Thrift abstracts previously available on FindmyPast and FamilySearch, and FindmyPast has added new indexes of surviving wills (including the large set held by the NAI/FamilySearch described above) and a useful set of links to the Fisher wills and Betham pedigrees from wills held by the National Library of Ireland.
I have also newly linked to some other sources that were available before such as some doctors' wills also on Ireland's Record Treasury, some probate details included in the tax records, soldiers' wills in the UK National Archives, wills of those who went to India in the British Library and various abstracts of wills in journal articles.
I hope that this is now a reasonably complete explanation of what is available with links to help you find things and suggestions on how to organise a search.
I would encourage anyone looking for Irish will and probate records to check here and anyone who has suggestions for improvement to let me know.
Many thanks to John Falvey for his help in this.
