The consistent names
Chocolate, cocoa and caffeine; grapes, raisins, sultanas and currants; onions, garlic, leeks and chives; xylitol (birch sugar); macadamia nuts; alcohol; and raw yeast dough all appear consistently on veterinary toxin lists.
These are not 'small amount is fine' foods. The standard advice for all of them is not to feed them at all.
Hidden sources matter most
Most accidental exposures come from mixed products rather than raw ingredients: fruit cake, trail mix, sugar-free gum and sweets, chocolate desserts, garlic bread, and savoury dishes made with onion.
Read labels before sharing anything, and keep bags, lunchboxes and holiday food out of reach.
If your dog eats something on this list
Contact your vet or an animal poison control service straight away, even if your dog seems completely fine.
Have the packaging, an estimate of the amount and your dog's weight ready. Do not induce vomiting unless a veterinary professional tells you to.