Smoked salmon and scrambled eggs, huge fruit salad with yoghurts, poached eggs with grilled tomatoes/mushrooms, and you can add wholemeal toast (healthy extra) or splinkle some cereals (healthy extra) on top of the fruit salad and yog, also cinnamon goes nicely with apple and yog.
Hope that has given u some inspiration , if not there is a breakfast thread on here that might give you some ideas.
You could make some muffins? They can be made ahead of time. You could have cheese, ham, mushrooms, spinach... To be honest my Christmas Day breakfast of choice is a selection box and a chocolate orange!
I use eggs, fat free cottage cheese, salt and pepper and whatever fillings I fancy. Poor into silicon muffin cases and bake for about 40 mins. They're yummy and keep for about 5 days in the fridge