I freeze soups, casseroles, breakfast items like muffins, biscuits and breakfast tacos, homemade goodies like cookies, etc. Usually when I cook a casserole, instead of cooking in a 9x13 I will cook in 2-8x8 pans and freeze a whole 8x8 pan for a complete other meal. I freeze my soups in Gladware freezer containers. Cookies and breakfast items I put in Ziploc freezer bags.
Beans freeze well too, i make a big ole pot of pinto beans with all the goodies...onion, ground meat, jalapeños, or whatever you and your family enjoy...then freeze in smaller quart size freezer bags. Perfect size for me and my DH. And as someone said a few replies back, the stack well once frozen.
I freeze in mason jars and aluminum pans. We do king ranch chicken, chicken spaghetti, Swiss steak, spaghetti sauce, chili, soups and stews. I have a cook book called fit and friendly freezable meals (or something close to that) that has a ton of freezable recipes in it.
I stock up on the ziplock freezer bags when they are on sale for $1 @ Kroger (then use my $1 off two boxes coupon of course). This sale only happens once or twice a year. I like the way the bags stack for soft mushy stuff like lentil stew or pinto beans.
If you bake a dish or casserole in a pan, line it with parchment then foil first. Freeze it in the pan then lift it out and place in a ziploc. When it comes time to reheat, put it back in the original pan to cook.