Mozzarella curd tends to be hard to find. The people who have mozzarella curd generally make mozzarella with it, and would rather sell you their cheese than their curd.
Our neighbors at the New England Cheesemaking Supply Company refer people to Todaro Brothers in New York, which sells fresh curd. Other sources we've tracked down online include Cheese Express and Golden Age Cheese Company.
We have received press releases over the years from companies that are announcing mozzarella curd for sale in grocery stores - but have yet to see it on any shelves anywhere.
Given the difficulty of procuring any mozzarella curd, do you really think you are going to find buffalo-milk curd anywhere? And who makes mozzarella from goat's milk???