Avocado's-especially can be toxic to birds, causing even death. In dogs it effects their breathing. Can also cause vomiting and diarrhea.
Grapes-can cause your dog to have kidney damage. This can eventually lead to increase urination and lethargy.
Onion Garlic-damages red blood cells, anemia, diarrhea, and are poison to both dogs & cats.
Even though this is not fruit or vegetable. Keep in mind anything containing
Xylitol-which can be found in sugar free gum, can poison your pet too. This ingredient causes increase insulin secretion, resulting in low blood sugar levels. This is especially toxic for dogs.
I hope these tips help!