Now that's a lot of food.
In t he UK after Christmas, my favourite is using leftovers for "cold meats and pickles", which you have with salad.
The star of this dish is "Bubble and Squeak", which is fried left over mash potato which we include cheddar cheese, spring onions and left over vegetables, broccoli, peas, carrots etc...
Also adding an egg and some plan flour helps bind it together. Here is a more traditional recipe:

