A few I know of are chocolate, onion, garlic, tomato, not too much tuna (mercury), not too much sugary food or fatty food. There is a very long list of 'human' food that is bad for dogs. Having said that our pup loves getting a bit of raw carrot, parsnip or apple (no seeds) when I am chopping veg and gets the occasional piece of cheese, a chip or pizza crust. He also gets boiled chicken, rice and veg as a treat. Best to search online or ask your vet.