I'm sure you'll get a wide variety of answers on this one. I, personally, only feed healthy treats. I have one with a sensitive stomach that cannot have chicken so I have to be very careful in what I choose for treats.
Mine all love raw carrots, they also love spoon size shredded wheat, but I don't give them that too often. I usually buy the Wellness/Old Mother Hubbard treats. Their favorite is the oatmeal, banana, apple and the peanut/honey (Wellness). They also love the charcoal treats from OMH, but it has chicken fat in so I have to be careful who gets those (if you have a dog with a fart problem, the charcoal treats are great to eliminate the gasiness).. But by far everyone's absolute favorite treat are Bah Bah Qs (lamb's lung). For chew treats, I buy pig ear puffs (basically their baked instead of fried and you don't have to worry about grease spots from them), lambs ears, small knuckle bones, and piggy tails. For training treats, I used the Charlee Bear egg/cheese treats. They're about the size of an M&M and all the dogs love `em.
I don't buy anything that's main ingredients are wheat, soy, corn, etc.
What's wrong with quail eggs?? :) They're healthy and the dogs love them. I have tons now since I stopped raising the quail. The females still lay but I have no use for the eggs so I just feed them to the dogs or cook them for myself.