Pasta:
Tomato sauce from a jar or from an onion, garlic, tinned tomatoes/pasata and some seasoning.
Creamy sauce using an egg (beaten) and some pasta cooking water.
Pesto
Just some olive oil or butter, possibly with some lemon juice
items to add include:
Jarred olives, jarred peppers, bacon lardons (Lidl double packs are very long life in fridge), jarred sundried tomatoes, tinned clams, tinned mussels, etc.
Nasi goreng:
Cook and cool rice. (It really is useful to use up leftover rice, or to plan ahead and make extra the night before)
Open tin of tuna - if in oil, use that oil to fry (added flavour and less waste combined!)
Onion, garlic, any bits of veg you have (sliced carrots, cauliflower or broccoli florets, shredded cabbage are all relatively long life)
Add half a tin of sweetcorn
Add the tuna
Add a couple of tablespoons of mild curry powder and stir well
Add the rice, stir well and cook until the rice is thoroughly hot
Local Asian restaurant serves this with a fried egg on top with DH likes, but it's just as nice without
Chinese:
Based on either rice or noodles
Fry onion and garlic (and ginger)
Add mix of long life veg (sliced carrots, shredded cabbage, broccoli, cauliflower) or tinned veg (including beansprouts or bamboo shoots) or frozen veg (peas in particular)
Add any meat/fish you have (tinned mussels, tinned clams, tinned or frozen prawns or squid, frozen white fish, frozen chicken, I often freeze leftover roasts in thin slices to add into mixed meat Chinese stir fries, vacuum packed duck breasts last a long time in the fridge)
Sauce - a sachet of something from supermarket (Blue Dragon or similar) or a jar of Uncle Bens or make something using a capful of Chinese rice wine, some soy sauce, oyster sauce, fish sauce, or similar, and some extra stock/water/broth if needed.
Thai red curry made using an onion, garlic, spoonful of thai red curry paste, tin of coconut milk, and then whatever meat/fish/veg is available and tins can be fine (but tuna is not a good one for this).
Bean tacos - fry a tin of four bean mix with an onion and a tin of sweetcorn and some fajita or taco seasoning.
Serve with wraps or taco shells.
If you don't have the relatively long life crème fraiche or sour cream in your fridge, either Old El Paso or Santa Maria sell a shelf stable version of sour cream. And the same company also sells a shelf stable guacamole if you don't have an avocado to smush with some garlic, lime juice, chilli and salt. Along with their salsa in jars or plastic tubs.
I generally buy my cheese in blocks rather than pre-grated as it lasts longer (especially hard cheese like cheddar for this, or parmesan for pasta).
And if you have any tomatoes or salad (maybe from garden/windowbox), its good to add, but nice even without these.
Just as an alternative to chicken or beef versions with fresh or frozen meat.
Curries using jars or packets of spices and tinned tomatoes or coconut milk (tinned or dehydrated).
Pizza made on a pan rather than in the oven - its more than 30 years ago since we did this in home economics, but you cooked the dough on one side and flipped it over. Put the tomato sauce on that, cheese, and toppings already cooked. When bottom of dough was cooked and cheese melted, it was ready to eat. Cooked ham (spam?), jarred peppers, jarred tomatoes, jarred mushrooms (antipasti), jarred olives, tinned prawns etc would all be good for this.
Risotto of all types.
Dried mushrooms (I use the rehydrating water, drained so any grit doesn't transfer, as part of the stock for added flavour), or antipasti jarred mushrooms.
Tinned seafood (prawns, mussels, clams, squid etc) or frozen.
Plain with just some lemon juice through it.
Butternut squash (very long lasting veg that doesn't need the fridge).
We also made sushi yesterday - we had fresh prawns but tinned would be good, and smoked salmon is also long life.