Our chili has leftover grilled steak, lots of bell peppers, onions and corn, black beans, kidney beans, diced tomatoes, a mild chili seasoning packet, and a couple tablespoons of barbecue sauce. That fed the kids a healthy meal almost once a week for years.
Leftover chargrilled steak is my go-to ingredient, too. Ground beef slow cooked with all the spices, then a good rare steak diced up and added at the last minute.
Not going to mention any of the other things I put in, lest the purists have a myocardial infarction.