Hi Bootus,
They can't have wheat, barley, oats, rye.
I try and look at all the great basics they can have meat, fish, eggs, milk, most yogurts, cheese, rice, potatoes, veg and fruit rather than thinking what they can't.
Gluten free pasta is great but don't overcook it.
Risotto
Egg mayonnaise
Pizza made with gluten free base
Pancakes for breakfast
Not sure whether you use sauces at times but Heinz pickle/Colmans tartare sauce/Heinz ketchup/Hellmans mayonnaise I was avoiding anything with barley malt/barley malt vinegar
Knorr or kallo organic stock cubes
Don't assume you have to buy everything from the Free From section a lot of day to day things are already gluten free.
Convenience - look in the freezer section, gluten free fish fingers, oven chips (not things like home fries with a coating), frozen veg, watch out for things like breaded ham and most sausages have wheat based fillers in but I think all supermarkets now have some gluten free ones in, baked beans.
Most breakfast cereal has barley malt extract in which I avoid. We use Whole Earth cornflakes(on the normal cereal aisle in Sainsburys), Free to enjoy cornflakes,
Doves farm flour
Treats or for parties - normal crisps (not hula hoops or similar) vanilla icecream usually fine but other flavours read ingredients, chocolate - cadburys is well labelled
Other favourites - Gluten free kitkat type biscuits, jaffa cakes, jammy wheels
Hope this helps