I have a book that's got about 50 foliate head photos from NYC, and no doubt there are more

Would that be Nightmares in the Sky? I picked it up in a charity shop in Lytham St Annes for 50p! A truly amazing book. I'm looking at Foliate Heads in a secular / municipal context too, and the North West of England seems particularly well served. Here's a few of my favourites:

Blackpool (Hotel?)

Preston (Waterstones)

Chester, Lanes

One the puzzles here is that whilst the Victorians were evidently very fond of Foliate Heads, they seem to be a feature of the Neo-Classical rather than Neo-Gothic, where one might expect to find them. As I mentioned above, the Neo-Gothic Roman Catholic Cathedral in Norwich is replete, but, in general, the buildings of the secular Neo-Gothic seem a tad bereft. In Manchester, for example, one might scour the magnificent Gothic Town Hall in vane, whereas the surrounding Classical buildings are particularly well served. This is just an observation of mine by the way, if anyone can provide examples to the contrary I'd be interested to know about them.