Welcome to TCS! I love the little tabby-tux in your avatar - what a cutie with an amazing paint job
Cats are obligate carnivores so meats cooked without garlic or onion make nice treats. When occasional diarrhea is a problem, you can add boiled white rice. For constipation, you can add a teaspoon of plain cooked pumpkin (avoid pumpkin pie mix which has the spices added).
I hope this helps
Stick with meat, with raw or plain cooked. Poached chicken is good.
Raw egg yolk (never raw egg white) or a whole cooked egg can be fed. Some cats like a bit of plain yogurt, cheese, even veggies.
People food should only be given in small amounts as an occasional treat. Too much can cause an upset tummy or nutritional imbalances.
Here's a list of what NOT to feed to a cat: People Foods to Avoid Feeding Your Pets It says not to feed raw meat but many people do feed cats and dogs a raw meat diet with no issue at all. Raw diets are popular with pet owners but not with many vets and organizations like the ASPCA.
If you asked my boys they would tell you donuts, Lay's potato chips, creamed spinach, mayo, mac and cheese, corn nuts, mashed potatoes...
"guys: you're killing me"
You can give them a little of your chicken if the seasonings are gone. No skin, no crust. They are obligate carnivores, so anything pure meat (beef, pork, alligator)is okay. The fat calories from the skin add up too quickly, and the crust is extra carbs. I usually give Vital Essentials freeze dried raw treats, but these guys try to pick out their own snacks. Foodies.
Some cats will eat anything offered to them or that they find on your kitchen counters, trash can, etc Bones, candy wrappers, paper towels used to sop up grease from a pan, a pan of just baked goods, etc. Cats just don't know what is safe and not safe for them. You need to be vigilant about keeping no-no foods off the counter and the kitchen trash can secured properly and other trash cans in the house emptied regularly or make a "no food / food packaging waste" rule for them. Discourage begging while you are eating your meals. If you do offer something, put it in the cat's bowl, not offer it directly off your plate at the table.