These were names given to boys as the first name. I've quickly looked through and pulled out those that appear to me to be Irish. Some of the names have multiple origins and are not only Irish but also used in other language. Some of the spellings include other languages, eg Ruaridh below, as parents thinking of naming their child Ruairà might like to know about Ruaridh. The data doesn't include any fadas.
Here are all the Irish spellings given to more than 12 babies:
Finn 788
Liam 690
Cillian 168
Conor 163
Cian 136
Denis 135
Lochlan 127
Rian 127
Malachi 126
Lachlan 110
Sean 103
Oisin 96
Tadhg 90
Ruairi 80
Brian 79
Niall 76
Fionn 61
Eoin 42
Cormac 26
Odhran 24
Dara 23
Mac 22
Ruan 18
Alasdair 17
Seamus 17
Senan 17
Art 14
Ruaridh 14