Taken from another post (or website I don't remember)
Master Food List - You may substitute freely within a category for variety:
I. Proteins—Chicken, tuna, fish, turkey breast, 93% or higher lean beef, egg whites, whole eggs,
II. Complex (Natural) Carbohydrates—This is a risky area. A complex carbohydrate is one that can be fully utilized by the body to be burned as energy. Some good examples are baked potatoes, sweet potatoes, brown rice, cream of rice, brown rice cakes, brown rice pasta, oatmeal, kidney and lima beans, corn, lentils, and peas.
III. Fresh Fruits - Apples, apricots, avocados, berries, cantaloupe, cherries, grapefruit, grapes, honeydew melons, nectarines, oranges, papaya, peaches, plums, strawberries. (Unsweetened frozen fruits are acceptable as part of your total fruit intake.)
IV. Non - Starchy Vegetables: asparagus, green beans, cabbage (all varieties), carrots, cauliflower, celery, cucumbers, kale, lettuce (all varieties), onions, peppers (green, red, jalapeno, etc.), radishes, spinach, string beans, squash (summer varieties only), tomatoes, water chestnuts and zucchini.
V. "Healthy" Fats and Oils: Flax seed oil, safflower oil, sunflower oil, walnut oil, olive oil, almonds, Brazil nuts, filberts, pecans, pine nuts, walnuts, flax seeds, heavy cream, real butter, and lecithin granules.
Also depends on if you want a clean bulk or just straight up bulk. A lot of people will find it hard to have a completely clean bulk as you must eat large portions of food and it can get pricey especially if your wallet is tight. There are some people that will tell you to just eat whatever you want, just as long as you get your calories in.