FISH AND SEAFOOD:
Check the ingredients on fish and seafood carefully and you will be surprised how often additives is added to even the most basic frozen or packaged seafood. I'm including canned fish in this list as long as it's msg, sugar and additive-free, keeping in mind that some of the cans for some of these products may contain BPA or other potentially harmful can linings, in case you're also avoiding that.
Premier Marine Canada Salmon
Ingredients: ATLANTIC SALMON
Great salmon with no additives. Farmed responsibly (certified by the Aquaculture Stewardship Council). The portions are individually vacuum sealed which makes them very convenient to thaw and use (although I cringe at the amount of plastic waste that generates - at least we can recycle them though). Premier Marine Canada also has Atlantic Cod and Tilapia in similar packages that have no additives (I'm not sure about their shrimp).
Catch of the Day - Frozen Tilapia
Ingredients: TILAPIA FISH FILLETS
It's amazing how hard it can be to find frozen fish with no additives - if you are buying frozen fish make sure ingredients are listed and check them carefully! This is one variety we use all the time for it's consistently good quality, before natural ingredients, wide availability and affordability. I encourage you to check the ingredients on any frozen fish you're buying - you'll be surprised how many varieties do have additives!
O & C Brand Shrimp
Ingredients: SHRIMP
It's remarkably hard to find shrimp without additives. And if you do, they tend to shrink significantly when cooked. We've had good luck with this brand, although I would recommend washing them very well before cooking (we've had a few times they tasted a little muddy otherwise, they live on the sea floor after all).
Allessia Anchovies
Ingredients: FILLETS OF ANCHOVIES, SUNFLOWER OIL, SALT
Anchovies can be a remarkably useful ingredient, especially Caesar salad and Puttanesca sauce, and can add a lot of depth of flavor to many recipes.
BOS Smoked Salmon
Ingredients: ATLANTIC SALMON, SEA SALT, NATURAL WOOD SMOKE.
Delicious smoked salmon, the way it was meant to be enjoyed, with no added sugar or processed ingredients.
Raincoast Tuna
Ingredients: ALBACORE TUNA, SEA SALT
It might seem reasonable to assume that canned tuna is just canned tuna, but it's often not! Many brands have additives and processed ingredients that contain processed free glutamate. There are a few that don't and Raincoast is my personal favorite. Not only does their tuna contain no processed ingredients, but it actually doesn't contain any added water or oil, it's about as sustainable as it gets (no bycatch and no habitat damage), it's 100% traceable from boat to can, and the cans are BPA free. And it's really delicious.. There are cheaper "before natural" brands of canned tuna out there, but sometimes you get what you pay for. If you are going for a different brand, at least check the ingredients carefully!
Clover Leaf Smoked Oysters
Ingredients: SMOKED OYSTERS, SUNFLOWER OIL, SALT
If you're into smoked oysters, these ones are pretty tasty, and they now come in BPA free cans.
S & F Portuguese Sardines in Tomato Sauce with Chili Pepper
Ingredients: SARDINES (FISH), WATER, TOMATO PASTE, SOYA OIL, CHILI PEPPER, SALT
If you happen to like canned fish, this brand is great and this variety is particularly delicious! If you're not so into spicy food, they have a few other varieties that are also Before Natural, just check the ingredients carefully. I'm not sure if the can is BPA-free.