I usually keep a variety of cooked, canned beans as well as bulk dried beans on hand. Dried beans are a lot of work, and require a lot of time, however, they are much cheaper than the canned versions. Beans are an excellent form of protein as well as a great additive to any stew, soup or dip.
Rice and Quinoa
Like beans, rice and quinoa can be bought in bulk and will last almost a lifetime uncooked. Most rice and quinoa varieties take 10-40 minutes to cook, depending on the type. These are both great essentials for meal preps!
If you do a lot of baking, and have the storage space, I recommend buying large bags of flour. Bob's Redmill offers a 25lb bag, which you can order online or through most bulk stores like Costco.
Nuts also offer a high amount of protein, but because of their high oil content, they are perishable. To prevent spoilage, you can store them in your freezer in an air-tight bag, which should keep them fresh for about a year. Also consider buying raw, unsalted varieties, because the roasting process can speed up decomposition.
I store my oats in air-tight containers in my kitchen pantry. If you like to have a lot of oats on hand, consider buying bulk BPA-Free air-tight containers (I buy on Amazon or eBay). For smaller storage, consider mason jars.
I use vegetable broth in most of my soups, stews, veggie patties, marinades, etc. I've found the most efficient way to buy these is at Costco. They come in a box of 6 packages of organic broth that don't have to be refrigerated until opening.
Dried pasta is almost always vegan. Because eggs and dairy have a high spoilage risk, companies rarely use them in dried goods. I recommend always checking the ingredients to be sure, but you're usually safe here. Also, I try to buy pasta (and most foods) with the least amount of ingredients listed. Many pastas are made with only 2 or 3 ingredients. Forget the stuff with added preservatives -- if your pasta is stored in a cool, dry pantry, it's shelf-life should be 1-2 years passed it's "purchase by" date.
Nutritional Yeast, aka "nooch", is usually made from sugar cane or beet molasses. Nutritional yeast is not the same as activated (or "baking") yeast. When it is ready, it is deactivated with heat, then harvested, washed, dried and packaged. It's often fortified with B vitamins prior to packaging. The end result is a sort of cheesy, nutty tasting, yellow powder that makes for an excellent cheese replacement in almost any dish.
I'm sure I don't have to go on explaining to any of you what peanut butter is, or how to use it. Peanut butter, or any other nut butter, is very high in protein and fat. It's good to have around, but just don't eat too much of it! Also, I recommend skipping the preservatives by either making your own, or buying a raw version instead of the popular name brand jars.
Dried fruits can either be purchased or made at home in a dehydrator or oven on low heat. They will keep for years if kept in air-tight containers. Dried fruits make for a quick easy snack as well as a great additive to homemade granola bars, oatmeal or cookies.
Dark chocolate is USUALLY vegan, but not always. Big brands such as Brookside, Hershey's or Ghirardelli often add milk fat (whyyyyy????) or calcium sorbate (an unnecessary milk-derived preservative) to their chocolate. And don't forget, many large chocolate companies are not fair-trade. Most chocolate comes from South America or Africa, and along with coffee, is one of the most exploited import foods. Fair-trade chocolate ensures that the money that American companies spend goes back into the communities of those who produced it. My favorite brand is Luker Official (sold at Sprouts and Specialty Produce). They offer fair-trade, organic, vegan chocolate at a fair price.
Crushed, Dried Red Pepper