Last week I discussed the National Archives of Ireland site specifically for census records. The site, however, contains a number of other databases. Always remember that most databases of Irish records do not include everyone. Read the description of the database to determine if your ancestor would have been included. For example, Diocesan and Prerogative Marriage License Bonds Indexes, 1623 - 1866 are almost exclusively Protestant, issued by the Church of Ireland.
ForWill Registers 1858-1900, almost all of the original wills prior to 1900 were destroyed in the PRO fire, however, those proved in District Registries may have a copy available. Wills proved in the Principal Registry (Dublin) however, do not survive. I have found a number of wills for Westmeath ancestors. Prior to 1858 wills and administrations were handled by the Church and after 1858 by a civil court system.
One of the major sources on this site is the Tithe Applotment Books. Again, not all of them are here and even though some of the locations that are currently in Northern Ireland are available the coverage is limited. Back in 2019 I wrote about the Tithe and if you are not familiar with it, you may want read the blog. I strongly recommend you use the "Browse" feature to see what areas are covered. This was before the standardization of locality names and the townlands are transcribed exactly as they appeared in the records.
A frequently misunderstood database is the Census Search Forms 1841-51. These have to do with the Old Age Pensions Act 1908. In order to be eligible for a Pension, an individual had to be 70 years old which would take them back before Civil Registration. One way to "prove" their age was their appearance in 1841 or 1851 census. Applications were made to the Public Records Office giving information about where the individual lived and the names of their parents and since this was prior to the destruction of the census in 1922, a search was made in the census records. Henry William Mackey (my 2nd great uncle) requested a search in the 1851census and listed his parents as James and Rachel Mackey and the location as Kinlough, Rossinver, Leitrim. The record was marked "NF" (not found)...William wasn't born until 1867! It did tell me that he was living in 1916, married, with his wife, Letitia in Belfast which I hadn't known.
In some cases if the family was found, the names of each individual in that census were listed with their ages.
The Valuation Office house, field, tenure and quarto books 1824 – 1856 were done prior to Griffith's Valuation and include the documentation for what was the Townland Valuation. Although there is some overlap with Griffith's this Valuation was primarily to value to land and buildings and did not name individuals unless their house was valued £3 (before 1836) and after that, £5. The majority of individuals did not qualify to be listed although sometimes they are named and crossed out as exempt. The field books will give you information about the quality of the land in the area where your ancestors lived that might tell you something about the type of farming.
The Soldier's Wills and Crew Lists are self explanatory in you have ancestors that might have fallen into those categories. The Catholic qualification & convert rolls require a bit of an explanation. They are two different resources and here is an explanation of the issues by Paul Gorry, a Professional Genealogist in Ireland.
Below is a video tour of the site.
Happy Hunting and Stay Safe!