@Anneekins Asian markets should have multiple varieties of oysters. Sometimes they have different names. As you can see here. Look for the shape and google the name when you are there!
Mushrooms is a good meat substitute as well, gives you a bit of texture I think.I will have to post some pics. There are some great meals you can make without meat. I make a killer spaghetti sauce with no meat and everyone who eats it like it just as much if not better than any meat sauce. Its really thick and hearty too. I grate zucchini as my meat substitute to thicken up the sauce and lots of fresh garlic,bell peppers,onions, thyme,oregano,basil, rosemary all from the garden.This year when I harvest my peppers I'm growing I will play around with some spicier sauces for the pasta sauce.