Pork neckbones are baked with onions, garlic, salt and pepper, (sometimes a little sage and thyme) and a splash of apple cider vinegar. Some folks boil them with the seasonings instead, but I think roasted makes a better flavor. And you make some excellent gravy from the pan drippings and serve over rice.
Beef neckbones are very tough meat but extremely good. Slow cook them in a 325 oven. Don't use vinegar on beef, but instead use a bay leaf, again onion and garlic, salt and pepper, and a little cumin doesn't hurt. You can use them in stew, you're going to SLOW cook them until they're falling apart.
Turkey necks: Boil them, pick the meat off the bones, and use it to make turkey and giblet gravy. Or turkey salad.