the cheese that many NY pizza joints use is Grande (whole milk mozz of course), made in Wisconsin and a bit more expensive than most other brands which some pizza joint owners cuss about.
I've never seen Grande in a retail market but the previous king of mozzarella pizza cheeses was Polly-O, that's a brand that might be easier to find, again whole milk mozz only.
I get a local family farm mozzarella the grocery store sources. I get that from a place that sells Boar's Head stuff. The farm is 20 minutes from where I live, right outside the city proper.
Then there is an Italian place that I buy fresh dough and cannoli's from. I use 3 different doughs. One is made fresh daily, 2 are frozen, plus I make a few. Jiffy dough is great, cheap and keeps, but it's not as good.
Okay, so I really like pizza and growing.