As far as bacon goes, I’ve read that if you cook 1/2 the bacon, then cover the raw bacon in the resulting grease, it won’t go bad.
I don’t have confirmation of that, though. I do have a pressure canner, and plan to can many meats over the next few weeks.
I remember my grandmother talking about covering meat in a crock with lard to keep it. That’s all I know about it though.