I batch cook a huge tomato sauce and freeze it in bags, you can just throw it frozen into a pan of cooked pasta with whatever veg you like. Bacon is good with pasta, or pre-made meatballs?
Slow cooker if they don't like casserole food I'd suggest mild curries (maybe?) or big joints of meat that you'd normally roast. Gammon in Coke, pork in cider/apple juice, beef in a beery gravy, anything like that would work fine. I did a spin on a SW recipe this week, chunks of chicken with onions/peppers/mushrooms and threw in chicken stock cube, a tin of chopped tomatoes and a can of Diet Coke, it was like a sweet BBQ-ey sauce, ds (4) hoovered it up.
You could cook jackets the night before or get the frozen ones and reheat. All veggies reheat well enough next day.
Sausages reheat ok as well. Iceland sell really nice salmon portions in garlic and herby dressing that you microwave in 3 mins, my son adores that with instant noodles or microwave pouch rice. They also do pre-cooked sliced chicken pieces that you can stir fry from frozen or just leave out to defrost. Obv no good if chicken is completely off the menu though!
The Jamie Oliver 15 min recipes are great. Frittata/omelette can be whipped up quickly with whatever randomness you've got in the fridge.
Wraps are good with whatever salady bits you've got, with chopped up breaded/battered chicken strips (again Iceland do some good ones in funky flavoured coating).
Lasagne, fish pie, cottage pie, bolognese, anything mincey really, reheats and most taste better next day!
Sorry if I've repeated anything from pp!