Veggie dishes: supergreen spaghetti (a Jamie Oliver recipe - chocka block with greens and so tasty and easy to make), Thai red chickpea curry, 3 bean chilli, leek and barley “risotto”, baked aubergine with tomato spaghetti
We usually have fish once or twice a week - usually something like baked salmon with jacket potato and veg (something like leeks or asparagus) or a pasta based side
Meat-wise, roast chicken thighs (with the skin!) are cheap, easy and super tasty. Sprinkle with olive oil and a little butter, and alternate the herbs/spices on top (along with a bit of salt and pepper) to keep it interesting (rosemary/lemon and garlic/za’atar are favourites - as is the Nando’s peri peri spice mix
). There’s a great za’atar chicken with chickpeas and garlic yoghurt recipe that is fantastic - on bbc food (Nigel Slater, I think).
Also mince is easy and versatile - eg chilli, spaghetti bol, stir fries, meatballs, burgers. I like to also use lamb instead of beef mince sometimes - lovely and tasty in a ragu with fresh pasta and some parmesan.
All of the above is easy to cook with relatively basic ingredients. Agree with previous poster that having an array of spices and herbs can make all the difference!