You can also freeze part cooked ingredients.
e.g. browned diced meat, can go into a casserole or a pie, is quicker and cleaner than browning and having smoking fat in the kitchen each time, or bits of turkey cut off the carcase for using when Christmas is forgotten, or slivers of baked ham or gammon for a minestrone later.
If you know anyone who has leftover wine (is there such a thing?) it can go in ice-cube trays for adding to stuff you're cooking later. You can also do this with stock or other liquids and use small quantities instead having to thaw out a big tub.
Chicken stock; minestrone base (with lots of solids but not the pasta), most other substantial soups. Sometimes gravy, if you have done something that makes more juices than you need, such as a large pot-roast, and make a vast quantity.
Part-used packs of barbie stuff
Cartons of milk
Fil up any gaps with double-wrapped sliced bread for toast (frozen bread goes stale very quickly)
You can make a week's worth of sandwiches, take out a packet in the morning and it will be ready to eat at lunchtime.
Opened packs of ground coffee (there is disagreement over this)
You know you can freeze things in a cooking post (if it has sloping sides so wilkl not crack) then tip out using hot water and wrap in film. When you want to reheat you unwrap and put it back in the pot, so no need to leave the pot in ther freezer