Pretty much every grocery store sells a variety of pre-bagged salad mixes these days. One of our favorites are the Caesar kits. Usually these come as a big bag of chopped romaine and a separate bag (inside with the salad) of toppings: croutons, cheese, ground black pepper and creamy dressing.
One of the main ways we like to finish such a dish is with the Seven Grain Tender product from Gardein. This is a vegan faux-chicken product that’s really easy to make, and a perfect healthy topping.