The Trader Joe's I shop at has two items I really rely on. Although they are not ultra low-carb, they work really well for me on the low-insulin (moderate carb/high protein) plan

One is the Zen Bakery Cranberry Apple Fiber Cake. One serving is only 80 calories and 9 net carbs with 5 grams of protein.

The other is their Greek Yogurt. The 2% yogurt has 16 grams of protein, 8 carbs, 4 fat. I mix it with a little Splenda and unsweetened, frozen cherries.

Both are very filling.