If you're going the online route, you might also look into getting green tripe. A lot of folks swear by it.
It is the stomach lining of a ruminant animal (usually cow or sheep). You may see bleached white tripe in the grocery stores, but
green tripe is not bleached or chemically treated. It's said that since it is not treated, all the digestive enzymes remain, which supposedly also helps the consuming pet's digestion. And since it's not bleached to kingdom come, it is not allowed to be sold for human consumption; but some raw pet food sites will offer it. It is usually sold in a grind mix with other organs and such.
Pancreas is very difficult to come by, because they are usually collected, dried, and processed into a drug to treat pancreatitis.
Lung is another organ that some raw pet food sites will offer. Again, it is usually a ruminant animal, so...
If you get the whole fryers or whole prey, some of those extra organs will be in the body cavity... just depends on who processes the carcasses for your supplier.
Personally, I've not gone the online route, as I have not been able to justify shipping cost when I can get reasonable items in town (even in the middle of the desert).