Not an exhaustive list, but here's some of what I usually have on hand (including fridge/freezer items that keep a long time):
- Pasta (various kinds but usually at least spaghetti and shells)
- Canned beans (I usually have black beans and chickpeas + sometimes others)
- Canned tomatoes
- Chicken stock (either in tetrapaks, cubes, paste or some other shelf-stable version) -- sometimes other kinds of stock (e.g. vegetable stock too) but usually at least chicken stock
- Salt, Pepper, MSG + a good selection of various dried herbs/spices/seasonings (e.g. basil, oregano, cumin, cayenne, garlic powder, etc.)
- Soy sauce
- Vinegar
- Olive oil
- Neutral vegetable oil
- Butter
- Canned fish (at least tuna and/or sardines)
- Cheeses (I usually have Parmesan, pepper jack, and American cheese slices that melt easily [e.g. velveeta or kraft singles or something like that] plus sometimes cheddar or Swiss)
- Peanut butter
- Flour
- Baking soda
- Yeast
- Chocolate
- Cocoa powder
- Sugar
- Eggs
- Milk (UHT lasts a long time)
- Salsa
- Canned or frozen green vegetables (e.g. peas, spinach, etc.)
- Rice
- Bread (frozen for storage)
- Dried lentils
- Dried fruit
- Cornstarch
- Ground meat (frozen)
- Tea
- Ketchup
- Mustard
- Mayonnaise
(may add more to this as I think of things)

Wasn't seeing it here on reddthat yet until I tried loading it manually, so I'm guessing the bot that automatically subscribes to new communities failed.