There's a preprepared salad mix, I think Costco carries it in Canada. The greens include shredded Brussels sprouts, kale, and purple cabbage. The add-ins are pumpkin seeds and dried cranberries. The dressing I can't remember for sure, I think it was creamy but there could have been balsamic vinegar and / or maple syrup involved. I suspect Trader Joes would have something similar.
Last Christmas, all four of my kids were home, from scattered across the country. They are each foodies in their own right, and cook everything from scratch. And each one of them said Mom, you have to get this salad, it's the best. And they were right. I do a rubbed kale salad with craisins and pine nuts, but this was better.
Of course it could be made from scratch too. It sounds similar to many mentioned above. But it doesn't need a grain (after all, the meal is carby enough already), and the veggies are hearty enough to stand up to the rest of the meal. Even salad haters go for it, but should you have leftovers (not likely), they won't wilt and you have lunch sorted.