Do roasted meditteranean veggies - they can be served as a side dish with meat/potatoes, in a tomato sauce with pasta, made into a veggie lasagna or used as the filling for a quiche.
Basically, I dice up (about 1cm dice to make it all cook evenly and reheat quickly) whatever veg I have but a reasonably "normal" batch and quantities would be:
2 large red onions
5/6 cloves garlic
2 courgettes
2-3 red/yellow peppers (mixed is nice)
large handful of cherry tomatoes, halved (maybe 20 toms?)
(an aubergine if DH/DD not eating, a large handful of mushrooms if I have them)
Season with salt, pepper, dried oregano (good 1-2 teaspoons), good glug of balsamic vinegar (1-2 tablespoons?) and good glug olive oil (doesn't need to be extra virgin, maybe 3-4 tablespoons?)
Mix them all together - if I have time to do it ahead, I will mix and put into a freezer bag in the fridge overnight and cook the next day as that allows flavours come together. Takes about 25 mins to cook at 180ish - adjust cooking times based on veggie size and oven temp (no problem cooking a bit higher for shorter, and absolutely no problem lower for longer) - it's a great dish to use up oven space when it's on for something else already.
Do you eat any spicy food at all? Your initial list is reasonably plain but curries and chillis freeze very well, and can be all sorts of different meats and veggies in them, or purely vegetarian dishes too.
I make HM potato wedges, and tend to start them off by chopping, seasoning (basic is garlic salt, pepper and then whatever suits the dinner I'm making so spices, herbs, or lemon zest etc as desired), adding a good glug of sunflower oil and microwaving (under cling film with holes poked into it) on high for 5 mins. They then get cooked in oven for 20-25 mins. But they can be frozen at the point of coming out of microwave.
How about fish cakes and other potato cakes? Flake your fish, tuna fish, crab meat etc into mashed potatoes with some spring onion, and depending on the fish, some peas, sweetcorn, maybe grated cheese. Season well. Roll mix into tablespoon sized balls, flatten, give the "flour, egg, breadcrumb" treatment and fry/oven bake. Or freeze once crumbed.
Something I also find useful is ALWAYS having a bag of breadcrumbs that I can grab a fistful as needed (I make it with stale bread that is going to be wasted otherwise). If I already have a decent bag, I will then go a step further and make up another bag with HM stuffing. A basic one - fried onion, garlic, seasoning, breadcrumbs and plenty of butter. I won't make it specifically Italian or suited to particular meats etc - but it can be used to stuff a few Portobello mushrooms and beef tomatoes as a fast dinner, or a butternut squash, or fast joints like pork steak or to put a crumb on a rack of lamb. You can adjust the seasoning to suit the final dish as you are putting it together (say adding some lemon zest and juice for fish, chopped dried apricots for lamb or lots of oregano and basil for tomatoes).
2 other things that are useful, especially if you would be using the oven, are a bag of HM crumble mix so that you can put together a desert in minutes (it cooks fine straight from frozen, just allow an extra 3-5 minutes cooking) and a roll of cookie dough that you can slice and bake from frozen (great for last minute bake sales or visitors).
Going back to savoury, I also find that having chops (pork, lamb), sausages, steaks, darnes/fillets of fish and chicken breasts and chicken joints (like part boned breasts or thighs) are handy to cook as pieces to be served as they are. But I also try to have a few bags, portioned out into family sized and 1 person sized batches, of different meats already chopped to make up stirfries or "saucy" meals in a hurry. So some chicken breasts I will chop up before I freeze, and pork chops, and also have things like prawns and squid rings, to cook quickly and leave out the chopping part as I get started.
I did have bags of plain tomato sauce made up which were really handy (and very fast to defrost as I had made them freeze flat). But I keep forgetting to make up a new batch. But great to just add meat/fish/veggies to in a hurry and serve over pasta.