There's a Dan Dooley concession in Galway: https://www.dandooley.com/. Good cars, fair pricing, and they do a good job of de-mystifying the insurance options - something that other companies usually don't seem to be able to do.
Another option about an hour and a half NW of Galway is the pretty little town of Clifden, which is right on the beautiful Connemara Loop Drive and close to the Sky Road, which is one of Ireland's great scenic drives. It's also not far from the ferry landing at Cleggan from which you can take the short trip over to Inishbofin - one of Ireland's better kept secrets.