Nothing on a deer, goat, chicken, rabbit, raccoon, possum... is poison, with the possible exception of the gall bladder. I've never known anybody to try one, and can't imagine anybody wanting to.
Otherwise, what you can eat from a deer is entirely depend on where you stand on the adventuresome/squeamish scale, and how hungry for organic free range protein you are.
If the animal's large enough, I like to get the liver frying with onions as soon as I get it out, so when the jobs done we get a reward. Brains make a good meal. Tongue is great. There' a lot of good muscle on the jaws. Out of respect, I feel like I should eat the eyes. I boil them in a soup, and try to offer them around. They're not bad, but I'm glad there are only 2 to a deer.
I go through all the organs before I start on the carcass. If you have a place you can hang the carcass, it's all to the good, because the carcass needs a few days to hang to get tender.
I eat heart, liver, spleen, pancreas, testicles. I've eaten tripe, but I haven't made it myself. I tried lungs, once. I didn't like it much, but then, there's so much meat to deal with then if you don't have refrigeration that it didn't seem much of a loss. Especially with dogs and chickens and cats who deserve a share of my good fortune.
I've never tried to use the large intestine.
If I'm out in the woods, I feel good about leaving the guts and the lungs out there, for the scavengers and distribute the nutrients to the trees.
If you've ever eaten a hotdog, you eaten all those body parts and more. And almost certainly by a non-organic, non-freerange animal