I will always have cheese, tinned tomatoes, pasta, rice, potatoes, onions, eggs and bacon lardons in my storecupboards/fridge.
Cheese - we like lots but the storecupboard one is a strong cheddar: Cheese on toast, perhaps with a dab of tomato relish smeared on bread (like Ballymaloe) underneath; Tuna melt; homemade pizza (using shop bought bases but putting together ourselves and choosing our own fav toppings); macaroni & cheese sauce with lots of mushrooms and bacon; over pasta bake; on top of breadcrumb topping of a smoked fish and broccoli pie; add into stuffing for stuffed tomatoes....and I haven't run out of ideas yet.
Tinned tomatoes for adding to a tin of condensed tomato soup (and the necessary water/milk, a saute'd onion and some extra herbs) to make a really good soup; tomato sauce for with pasta (I make batches and freeze - can do as pizza sauce, or for pasta with all sorts of veg especially mixed roasted mediteranean veg, chopped sausages, bacon pieces, chicken, prawns, seafood mix); bolognaise sauce; add it into quite a few different curries including Lamb Rogan Josh or Chicken/Prawn tikka masala.
Pasta: Mac'n'cheese; pasta with versatile tomato sauce as above; pasta bake; plain with a dash of olive oil and scattering of parmesan; or just a spoonful of pesto.
Rice: base for curries; chicken and mushrooms in a white wine/cream/tarragon sauce; Chinese stir fries; an Indian stirfried rice dish called Nasi Goreng to use up bits and pieces of leftovers/last bits of fresh veg; rice pudding.
Potatoes: Served beside dinners as mash, boiled or roasted; stilton and ham potato bake using Christmas leftovers; homemade chips; homemade oven baked wedges; baked potatoes in foil on BBQ; diced into Spanish omlette; and loads more again
Onions are the basis of almost everything - I often do a decent batch of sautéed onions and freeze in 1 cup portions (as roughly 1 onion) to start off dinners fast when home from work. Homemade onion rings. Fried onions on steak or burgers. French onion soup.
Eggs are very handy to do so much too - omlettes, fried or scrambled for everything from breakfast, lunch and dinner; Spanish omlette as more substantial; quiche filling; pasta carbonara; egg fried rice (surprisingly easy!!); or baking. Even without getting complicated about chocolate mousses or soufflés.
Lardons are a great standby to make a fast dinner and keep ages. Gorgonzola pasta is fast (fresh pasta boils, and 1 pack lardons fries, while you mix a pack of gorgonzola with a couple of tablespoons of double cream and melt the 2 together in a pot with 1 tablespoon of melted butter, add a handful of grated parmesan, season (pepper only - plenty of salt in cheese and bacon), drain pasta, take bacon from pan and leave fat behind (can use for roast potatoes another time instead of duck/goose fat if you hate to throw out) and mix all together - dinner in 7 minutes, or 15 if you use dried pasta). Add into scrambled eggs or omlettes. Use in pasta carbonara. Add into chicken pie. use to make a BLT in a pinch. Throw into a tomato sauce with some peas/medditeranean veg/mushrooms with pasta. Add into lasagna sauce for depth.