I pretty much feed tongue to tail on most animals. With larger prey animals (roughly those over 100 pounds. ie. cattle, deer), I tend to avoid large, dense bones. Some dogs know to just gnaw on those, others get too zealous and could break a tooth. A "know thy dog" situation.
Something of a bigger issue to me is avoiding meat that has been enhanced with a lot of sodium or something special to season it (meant to appeal to human consumers).
Turkey would be a good next meat to introduce. I primarily feed turkey necks because of cost (I can order a 30# case for $30 at the grocery store). Wings are pretty boney. Drumsticks are OK, but dense for some dogs. I have fed whole turkeys before without issue (broken down, but all the parts).
I've not had the opportunity to feed beef neck (no where to get it), but I have fed oxtail.
I've fed whole rabbit, (young) goat, deer, duck, and chicken. I've fed beef muscle meat (pretty much all "meat" is muscle), tongue, liver, tripe and tail. I primarily offer turkey necks, though I've used the whole animal on occasion. Lamb is usually a steak and tripe. Mice (for the cat) and quail have also been fed. There's probably more I'm forgetting, but I hope this helps. The bulk of my "rotation" now is beef, rabbit and poultry (duck, chicken, quail), though deer and fish have been thrown in there.
Below is some general raw feeding advice:
PMR ratios are 80% muscle meat/10% bone/10% organ. You may need to adjust these ratios slightly as each dog’s needs differ to some degree. Some people feed “balance over time” (i.e. over the course of a week), whereas others balance out the correct ratio for each meal.
At least three meats in the rotation--but more is better. Red meats are also supposed to be more nutritious. Start with one protein (whatever is readily available) and add another when you feel your dog is ready (e.g. every other day or week).
Make sure to give liver at around 5% of diet (either feed weekly or daily). This can be from any species. You may offer small amounts (e.g. bite-sized pieces) from the start and gradually build your dog up to the recommend amount.
Chicken feet (and duck, if you can find them) are a good source of glucosamine and chondroitin (for joint health).
For conventionally raised meat (like you get at the grocery store), offer some salmon oil or oily fish (e.g. mackerel) to the diet for omega-3 fatty acid to help balance the omega-6. Too much omega-6 in the diet can cause inflammation, hence the need to balance it. Grass-fed meat animals have a better omega-3/omega-6 ratio which shouldn't require supplementation.
Work Wonders by Dr. Tom Lonsdale
Raw and Natural Nutrition for Dogs by Lew Olson, PhD
Canine Nutrigenomics by Dr. Jean Dodds
I wish you guys all the best! Let us know if there is anything else we can help with.