At one point my DH and I had 5 very little ones, they were 3,3,5,5, and 6. Obviously they each had their likes and dislikes and there was just no way to cook for that many people individually. So my goal was to always make 1 thing that they liked with every meal, but only enough of it for one serving, then they had to eat what was made or go without. i had to go so far as to eliminate snacks to get even this to work though, but after they got over not wanting to try things they figured out that they actually liked a LOT.
other little ideas, if they like nuggets, dice up chicken and make your own with panko bread crumbs and bake them. You can add parm cheese and put over pasta for chicken parm, make slightly larger ones and stuff with ham and swiss for cordon blu, ect.
Fries, try sweet potato, if you are ok with it just introduce them as orange french fries.
They make purple cauliflower, it's grown that way, and tastes the same but the color might make it more fun.
shred or very finely chop carrots, broccoli ect. with noodle dishes
add ham or whatever you like to grilled cheese, or switch it up by making the grilled cheese on a pita or wrap (you can sneak in meats and veggies later)