Pork Liver and Fat
Any decent butcher will have these things. I use Whitehouse at St Lawrence Market, for example. However, it will depend what kind of pork fat you're looking for; Whitehouse can only sell you a whole belly, for example. I know that The Healthy Butcher will also sell you these things, including pork belly in smaller quantities, but I also know that prices at The Healthy Butcher are pretty steep, if you're on a budget.
The Healthy Butcher
565 Queen St W, Toronto, ON M5V, CA