These are my 2 favorites:
Kim Phat: 7209 boul. Tachereau,Brossard, Québec, J4Y 1A1
This is a big asian grocery store, They have quite a choice of mock-meat. They also have a huge selection of soy products.
IGASupermarchéPagano Shnaidman : 5800, Cavendish, Côte St-Luc, QC,H4W2T5
This is a regular IGA however since they are in a very jewish area, they have a vast selection of kosher items. As a result, they have lots of frozen pareve (neutral) food: mock-meat, entrees, side-dish. They also have plenty of dairy cheese made vegetarian rennet.