As well as Dublin city Thom’s includes listings for various towns in county Dublin, and also Bray / Little Bray. The listings are often not as detailed as the listings for the city, e.g. street listings only show for larger towns. As a sample see images and some transcripts from the County Dublin section of Thom’s 1848 here
Not everyone is listed in these directories, e.g. you will not usually see a listing for someone that was a labourer or living in a tenement or small cottage, and in addition not all the streets are included so while there’s a full listing for ‘important’ streets like Grafton Street, smaller side streets and lanes often are only mentioned as a junction off a main street or a listing similar to ‘seven houses in tenements’ or ’24 small cottages’. The later directories include more names and streets – e.g. Thom’s 1943 is more than three times the volume of the 1848 edition.
Also included in Thom’s are other sections covering lists of names and residences for all of Ireland of Priests/Ministers (CofI, RC, Presbyterian, Methodist etc), Magistrates, Attorney/Solicitors, Barristers, Medical Practitioners etc, and also officials (boards of PLUs, registrars, Medical Officers & Registrars etc) for Municipal Towns, Boroughs and Counties.
Other directories I can check include Pettigrew & Oulton 1834 & 1840 (see images for the street listing for these here ), and several Watson / Treble Almanacks between 1783 and 1829.