Hi,

Facebook has a feature where you can list the given names associated with a particular family name:
https://www.facebook.com/family/
provided the user's privacy settings allow this.

I took a few hundred Irish surnames starting with "Ní " and recorded the frequency of the given names. The results are listed below with the most common names at the top.

Common Male Names here: viewtopic.php?f=28&t=3205

Niamh
Aoife
Sinéad
Aisling
Emma
Deirdre
Áine
Ciara
Siobhán
Eimear
Máire
Caoimhe
Róisín
Bríd
Sarah
Sorcha
Orla
Gráinne
Clár
Lisa
Fiona
Amy
Eithne
Maria
Caitríona
Karen
Edel
Gillian
Eibhlín
Caitlín
Elaine
Clíona
Kate
Neasa
Kelly
Brídín
Dearbhla
Úna
Saoirse
Lorraine
Michelle
Dee
Síofra
Maire
Mairéad
Emer
Laoise
Méabh
Danielle
Mairead
Cáit
Oonagh
Louise
Cíara
Marian
Íde
Laura
Jess
Doireann
Rebecca
Rachel
Catríona
Martina
Eileen
Clíodhna
Cliona
Cailín
Níamh
Tara
Aifric
Ellen
Orlaith
Muireann
Eilís
Caroline
Brenda
Dearbhaile
Jessie
Andrea
Katie
Hazel
Carol
Christine
Christina
Cliodhna
Meadhbh
Mary
Cristín
Jenny
Ailín
Charlotte
Pádraigín
Éadaoin
Máirín
Tríona
Shona
Nóirín
Sharon
Dawn
Áine Máire
Shóna
Nóra
Ailbhe
Lorna
Seána
Leah
Gemma
Shauna
Bláithín
Deborah
Aoibheann
Clodagh
Nuala
Olivia
Aine
Claire
Roisin
Helena
Becky

Of course, you have to bear in mind that, while these may currently be the most popular female names in Ireland, several of them are not Irish names ("Helena" and "Olivia," for example), and some others are anglicizations ("Shauna," for example). There are also fadas missing on some of the Irish names.

Redwolf

Indeed! Names missing fades usually appear again higher up in the list with the fadas included.