Here’s a link to my very own attention whoring " ask me" thread.
Trawl through that or if you want to be more specific in your request, I’ll be happy to help with taylor made recommendation though I’m only useful at the traditional diddly-ay end of the market.
Try Irish Music Central which has an impressive up-to-date list of the up-and comming stars as well as some more established artists. It includes offical links to all the bands mentioned below.
My favourites of the ‘new’ bunch are :
Gemma Hayes
Damien Rice
Paddy Casey
Damien Dempsey
Mic Christopher
Ten Speed Racer
Check out The Frames and Ash too !
I’d hate to upset anyone but Capercaille are Scottish not Irish. (“Irish” is not a synonym for “Celtic” ok folks ?)
If ‘Irish’ is really what you’re after in addition to those previoulsy mentioned try out The Saw Doctors they are as Irish as they come - and good looking lads to boot 
PS For a wider perspective listen to Celtic Heartbeat, a show on BBC Radio Wales - you can listen to the show which is only an hour long, any time and the site gives a playlist so you can follow up anyone you particularly liked. (Site seems v. slow at the moment tho’ :dubious: Maybe wait a wee while)