What can black labs eat other than dog food?

They will try to convince you they can eat anything, but here's my standard answer:
Human foods in large quantities are not really good for dogs, but in controlled amounts the following should be fine: cooked meat, carrots, apples, peanut butter, rice, cheese (although I have heard of dogs being allergic to cheese, not sure if that's true so I'd ask a vet first)
Those are the favourite human-foods of most dogs. There are others they can eat though.
TOXIC: onions, chocolate, garlic, cooked bones...that's all I can think of off the top of my head. If you're not sure, don't feed it to them.