Ayla, try these...
Pork belly. It's what bacon is made from. You can cook it like a roast, or slice it up and make your own bacon.
Beef brisket without the fat trimmed off.
I am going through a bunch of wonderful sausage now as well. Very fatty and wonderful tasting and only about 70-80 grams protein per lb depending on the meat (beef is more, pork and lamb less). Just eat about half that cooked in butter or coconut oil.
Any animal's tongue or organs.
Or just eat the skin off of the animals sans the meat. Fry chicken, turkey, or pig skin in oil until crispy and eat like they are chips.
Duck and goose are pretty fatty overall so stick to the thighs and legs and you might do ok.