We are all veggie and ds1 although not extreme in his pickyness manages to refuse enough things to make planning a family meal a nightmare.
His favourite foods are all pasta and/or cheese based really, so macaroni cheese, pasta and sauce, lasagne, tortelloni etc.
I buy passata and chopped tomatoes in tetra packs with ready added garlic and herbs (they are really cheap in Tesco and don't have the high salt content and additives often found in ready made pasta sauce). Then I steam some vegetables and add them to it. If he won't eat the vegetables, you can blend them first and the tomato/herbs disguise the taste. I usually grate some cheese on top for protein and have he's just recently started tolerating me adding quorn chicken-style chunks to the sauce as well. I occasionally buy a three cheese capelletti to keep in the freezer as an emergency/quick meal as well. He calls them cheezy parcels.
Lasagne is a great one for adding lots of vegetables into the sauce and I often add well cooked red lentils in as well, although not too many as it changes the texture (ds is very sensitive to food textures).
He also loves vegetable frittata, or oven baked omelettes, which I add plenty of cheese and a good slosh of milk to.
Quorn dippers are a good one for an occasional treat.
We have also just started making fajitas made with quorn, which strangely ds1 really likes, but ds2 hates the salsa and the sour cream, so I just cook up some red onion, red pepper and green peppers and mushrooms and let him have some ketchup on his instead.
Another favourite of both boys is risotto, either with peppers, tomatoes, spinach and courgettes (chopped tiny so not really noticeable) or butternut squash. Neither of the boys likes parmesan, so they have normal cheddar grated on top of theirs.
Also, home made pizzas are well loved and for some reason he will eat obvious chunks of red pepper on them, as long as there is plenty of pineapple stacked on there as well.
All my dcs loved avocado and banana on either rice cakes or toast, but ds1 has just decided he doesnt't like it any more.
Am I right in thinking you were considering going gluten free as well? If so, all the above meals can be made with gluten free alternatives, as ds1 was gluten free from November through February of this year, then back on gluten for his coeliac test and is now about to go gluten free again.