I am guessing you need things that are easy to do in large quantities and can be kept warm for a certain length of time?
How about stew and dumplings (or cobbler) or casseroles? These can be made meat (sausages, beef, chicken, pork, etc) or vegetarian (root veg, mediterranean veg, etc). I would suggest savoury rice (a bit like risotto but using long grain rice and tin tomatoes) but perhaps this wouldn't be best for keeping purposes?
Meat: large pizzas that can be cut up into slices and served with salad, enchiladas, cottage/shepherds pie italian style, pork chops in cider, paprika chicken, toad in the hole, moussaka
Veggies: pizza (as above just different toppings), red onion and cheese tart, savoury crumble, glamorgan sausages, stuffed bell pepper, aubergines, tomatoes or courgette, nut roast, spinach and ricotta lasagne - I think quite a lot of meat dishes can be made vegetarian just by using different veg instead of meat (eg, cottage pie, enchiladas, as above)
Puds: cheesecake (various flavours), rice pudding, apple pie and custard, jam roly poly, different steamed/sponge puds, crumbles, baked apples, egg custards, chocolate mousse, profiteroles
I will have a think of some more but I am sure that will keep you going for a bit!
Helen