Keeping the freezer organised can be a problem for me, to often it seems to become a black hole of food amnesia if I don't keep on top of it ALL THE TIME. I have to force myself to use the freezer properly, that being said I do enjoy having it all efficient and fabulous! As well as the inevitable cache of frozen vegetables (so useful, I don't know what I'd do without them), homemade stock and the boines to make it with, I keep hunks of meat bought when there are good deals to be had, and a stash of both sweet and savoury crumble topping, ready mixed to be used from frozen.
I don't very often cook specifically for the freezer, though that time of year when I do is fast approaching. More often what I do is double up on things I'm cooking anyway; pies, casseroles, chili con carne and bolognese sauce (to name a few) are as easily made in double or triple portions as in single and then I've an extra meal or two to parcel away, in anticipation of a busy day.
Today I had a good quantity of leftover meat from a whole turkey leg joint I cooked for our Sunday roast at the weekend so this, combined with a tin apiece of ham and sweetcorn, plus a little leg-bone stock to make a savoury sauce went into two pies. The pie for tonight's dinner is in the oven as I type this, and you can see the other in the freezer picture above. I lined the (oiled) pie tin with some (oiled again) foil, then open-froze it in the tin once I'd assembled it. Once hard, it's the work of a moment to pop it out of the tin and wrap it in more foil. Thus, my pie tin is not buried on Hoth for weeks on end!