Chinese-style stir fry or chow mien style meals with noodles / rice / veg ... lots of variations you could try if you google for ideas.
Would they eat veg chilli and rice?
Veggie sausages, beans, mash
Egg, chips, beans
Breaded fish, chips & peas (or mash and beans)
Macaroni cheese if they'll eat white sauces? Use spaghetti instead of macaroni if they don't like shapes. Sort of a veggie carbonara! Add mushroom and peas in for two portions of veggies. My mum used to cut up fish fingers and put peas in my macaroni cheese. Sounds odd but it was delicious, one of my faves for years! (I might have it for dinner this week now, haha)
What about veggie fajitas / tacos etc? I love mine with mushrooms, onion, pepper, sweetcorn. Cheese on top, avocado for added goodness if they'll eat it. Cook the veg altogether in a frying pan then take out kids' portions without any (or much) spice mix on, turn add the spices for you and DH after. I serve with salad too.
I make a lot of stews, curries and Moroccan tagines in the slow cooker.
Veggie stew. I serve with Sunday lunch style veg and mash. I don't make the dumplings, I buy aunt Bessie's frozen ones. https://www.bbc.co.uk/food/recipes/butternutsquashhand468133
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Slow cooker veggie lasagna. this was amazing. Dunno if your kids would eat it, but it was so tasty I'll add it anyway. _ https://www.bbcgoodfood.com/recipes/slow-cooker-vegetable-lasagnee_
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Moroccan chickpea tagine. I serve this with rice. https://www.bbc.co.uk/food/recipes/slowcookerrchickpea_12414
Basically, you can pretty much recreate any meal with chickpeas, mushrooms, etc. Except for Sunday dinner! For that, I get Tesco's nut cutlets from the freezer section. (I tend not to eat a lot of soy or quorn as I don't like it much) you need cranberry sauce with it tho! They're good for a quick midweek dinner with mash, peas, carrots & cabbage.
For a treat, I do love a good "fry up". Hash browns, beans, eggs, toast, fried mushrooms, tomato and veggie sausages. (Only ones I like are Linda McCartney's rosemary ones from the freezer section, and you need to do them well done imo!)