So many Irish titles once used are now extinct that were associated with the British Royal Family.
The main one's I can think of
Dukedom of Connaught/Connacht
Earldom of Athlone
Earl of Castlemaine
Earls of Ormonde (The Boleyns)
Earl of Munster
Were the Boleyns at all Irish by blood? I know they originated in Norfolk but did they marry into an Irish family or have Irish ancestry?