Canned tomatoes
Dry pasta
Rice


These are the three stables in my house. You can make thousands of different meals with these three basics. Or if you have NOTHING else to add, you can always just do a quick and easy pasta and homemade sauce. So I should probably add my spice rack to that list - most importantly: morrocan spices and mixed herbs.

Otherwise, we always try to have:
eggs
bread (in the freezer)
chicken breast (freezer)
meat (freezer)
mince (freezer)
frozen vege
Tomato sauce

With these things and the three other basics we keep in the pantry, we basically make nearly all of our meals.
Ie, stir fry, spag bol, eggy bread (aka french toast), meat and vege, pasta bake, jaffles, etc...

Failing that, there is always weetbix and milk.