I generally find rice or potatoes most filling, so I plan meals around those. Jacket potatoes are amazing with almost anything (and plenty of cheese). Curries are great on both (and are a great vehicle for tons of veg), but flavoured rice with beans or lentils (mejadra) are a really filling side to meat/substitute/roast veg (or even on its own, though a little boring). Less healthy but filling is the classic (veggie) burger/sausages-chips-beans (of the baked variety) combo. Make a simple salad to go with it to make it more "healthy" (my go to is sweetcorn and red jalapenos with simple dressing, or store bought coleslaw).

I'm disabled so prep and cooking are a lot for me, so I mostly use frozen and tinned products which a lot of people discount as a bad choice, but find a way to flavour them nicely and they're super versatile (and still perfectly nutritious).