The best, easiest to raise is rabbits, then birds, crayfish/ yabby , catfish, carp, hogs.
All but the rabbits will eat anything to stay alive, all of them breed............well
like rabbits. Birds are the hardest to raise, because you eat the eggs, but you can replace 50 hen in three years, if you set one or two hens a year.
Crawfish will eat everything in a stream, then eat each other, so dig a hole/pond, fill it with baseball size rocks & feed the crayfish the innards of any animal you butcher. Wild Hogs are not bad here, but in some swamps in the deep South, they Have to kill 35% of the herd to keep them in check, or they will be up in their yards, eating your trash, pets & you.
This is not a joke & no one is laughing in that part of the south.
So they may keep people alive for a long time, but the rest of us will need to grow our own hogs. Sheep & goats are good for beast of burden, wool, meat & milk, but I do not know a lot about them. Cattle I know more about, but that would not fill chapter in a booklet.
I will not eat dogs, cat & horse/mules, unless there are no vegetation left for me to eat.