I do this alot, usually on a Saturday or Sunday. I'll roast a chicken in the oven, put a roast in the crockpot and make a pot of soup or stew on the stove. When the chicken is done, I'll pull the meat off the bones and use it for various recipes which can be frozen and reheated and I'll put the bones, juices and skin back in a pot, cover with water and cook for soup stock. I divide up the soup and freeze. And I drain the soup stock and freeze that too. In the winter, I like to make a big pot of chili and divide into portions and freeze.
You can also do this with fish - bake it in the oven, then chop into pieces and freeze and use to make things like fish pies or chowders or casseroles.
I make up cookie dough, roll it into balls or slice it, then freeze.
You can make lots of casseroles and freeze them.
And whenever I cook, I always prepare twice as much as we will eat that night and put half in the freezer for next week.
Make sure you mark your packages with the date you made it and what it was. Rotate it in your freezer.