Here’s an interesting newspaper article from Limerick talking about his relics.
The Irish Dominicans in Limerick have his pectoral cross, which was passed down in the O’Brien family from a lady who was able to see him before he died. From that time, and as relics of the local Dominican martyrs from St. Saviour’s Priory, they also have the priory’s chalice (aka the Sarsfield Chalice) and the priory’s statue of Our Lady from that time.
The oak statue is now known as “Our Lady of Limerick.” There’s a Catholic parish in Glenns Ferry, Idaho which is named for this real survivor of a statue, as well as for Our Lady’s title! Here’s a nomination of the church building for historic status that includes a nice black and white photo. (It’s currently part of a parish cluster with Our Lady of Good Counsel in Mountain Home, Idaho.)
Unfortunately, the Irish Dominicans have decided to close St. Saviour’s Priory, so presumably all the Dominican-owned relics will be moving out of Limerick.
I haven’t been able to see online whether St. Saviour’s Church will also close, or whether Our Lady of Limerick will have to travel elsewhere. It depends on whether the Order or the Diocese owns the church, I suppose. Here’s a page with more history of the church and of Our Lady of Limerick, including how she once went underground.
Here’s another article about Terence Albert O’Brien Park in Limerick, right across the street from the place where he died on the scaffold.
Here’s the park on Google Maps, more generally known as O’Brien’s Park.