Given how much attention toxic food lists reasonably receive, it's worth balancing that with knowing which common human foods are genuinely fine for cats in small, occasional amounts, since not everything outside a commercial cat food bag is dangerous.
Plain cooked meat
Small amounts of plain, thoroughly cooked chicken, turkey, or beef, without seasoning, onion, or garlic, are genuinely fine as an occasional treat, and some cats show real enthusiasm for this simple, familiar protein source.
Plain cooked fish, in moderation specifically
Cooked fish is fine occasionally, though not as a dietary staple, given both mercury accumulation concerns with frequent feeding and the fact that too much fish can contribute to a nutritional imbalance if it displaces a meaningful portion of a complete commercial diet.
Small amounts of plain cooked egg
Fully cooked egg (never raw, given salmonella risk and a specific egg-white enzyme that interferes with biotin absorption) is a reasonable occasional protein treat in small amounts.
Plain pumpkin puree
Plain canned pumpkin (not pie filling, which contains added sugar and spices) is sometimes used in small amounts to support digestive regularity, and most cats tolerate small servings without issue.
Small amounts of cooked, plain vegetables
Steamed carrots, green beans, or peas in small amounts are generally safe, though cats have minimal genuine nutritional need for vegetables given their obligate carnivore status — this is more about safe occasional variety than nutritional necessity.
Why moderation genuinely matters even for safe foods
Even entirely safe human foods shouldn't displace a meaningful portion of a nutritionally complete commercial diet, since cats have specific nutrient requirements (taurine, certain vitamins) that human food, even when safe, doesn't reliably provide in adequate amounts.
A practical guideline for treat proportion
A commonly cited general guideline suggests treats, including safe human food, should make up no more than about 10% of total daily caloric intake, keeping the nutritionally complete commercial diet as the clear foundation of your cat's actual nutrition.