Any greens you like. There are so many kinds of greens.
Arugula has a peppery taste, butter is tender, sweet and crisp, Romaine has a slightly bitter flavor. Your favorite or a mix of your favorite makes a great salad.
How about the dressing?
If you are are consuming no oils-use the juice of a citrus (lemon, lime, orange) + a bit of its zest or a beautiful vinegar with garlic, herbs and spices. If using oils, add the above to your oil for a gorgeous dressing. Splash versus drench your greens. Let the greens be the star and the dressing the supporting cast. The more muddied your herbs and zest are the more aromatic they will be in the salad. Salad dressings are usually 1 part acid (lemon or vinegar) to 3 parts oil. Example 1 tsp lemon juice to 1T oil. Use a 1 to 1 ratio of herb to acid. It’s very hard to use too many herbs! Enjoy!