One of the more unique repositories in Dublin is the Genealogical Office (GO). This is part of the National Library of Ireland www.nli.ie/en/intro/heraldry-introduction.aspx
Within its vast collections you will find miscellaneous extracts, histories, genealogical collections, and pedigrees. At the library many people find resources which help to circumvent the 1922 Four Courts fire, which destroyed so many primary records.
What you will find at the GO are genealogies for wealthy and landed families. Many of the genealogies include both ancient English and Gaelic families. It is mainly a Protestant source. What you will not find are genealogies for the average common tenant farmer. The exception to this will be when a more common person intermarried with a landed family. For example, a Presbyterian minister’s daughter married into a more prominent Church of Ireland family. I have seen this, so it could be properly argued that the Presbyterian family was not of the lowest tenant class to begin with.
The GO manuscripts consist of records, now destroyed, which do list the tenant class. For example, common people will be found in a GO transcript for the 1740 and 1766 census for a given parish. The GO records have been microfilmed and are at the Family History Library www.familysearch.org
If your ancestors were Protestant and moneyed, then I suggest you check the GO collections. If the ancestors were of the tenant class, I probably would not.