@roomtempmayo, The wild-caught red Argentine shrimp are very healthy, IMO.
I'm gonna to sound like such an elitist (perhaps I am!?) but I mostly only buy organic and humane-raised, and Costco is one of the world's largest sellers of organic food. So, besides the above wild-caught shrimp, and their wild-caught salmon, I buy a LOT of their organic produce, EVOO, avocado oil, coconut oil, oats, oat milk, 1/2 & 1/2, cheese, yogurt, butter, various kinds of nuts, almond flour tortillas - ALL organic. This level of organic variety is hard to get in most mainstream groceries outside of Whole Foods. However, when I was in TN recently the Costco didn't stock the same amount as in the Bay Area.
My main disappointment is they don't sell decaf organic fair-trade coffee here - can't imagine why, I'd think it would sell well. They have it online.