What did people feed their pets before pet food?

Like many said, table scraps. Many were left to fend for themselves in an area deemed fit for them to live. Also whatever they could hunt or grow for themselves was often shared(basically table scraps lol). Some like cats were only purchased to be pest control, they'd get whatever mice, rats, snakes, bugs, rabbits or birds they could catch. Some would be cared for in months were food was scarce, table scraps again mostly. In some places even today animals are kept like this. In Alaska many fish for winter food for their dogs instead of using commercial foods and give them parts of animals like moose, elk, bear and deer that people don't eat. Often hunters who used dogs for it would share the kill.

For farm animals, food was always grown and stored for them in winter months, even way back in the day, hay and oats and the like. For most of the year they were set out to the pasture to feed themselves on the grasses and greens that grew in the area. Many still do this to this day. In fact I think all do it the same to this day, otherwise they'd be spending hundreds of thousands of dollars to feed their herds through the year.

Most pet foods are basically "human foods" made more cheaply and marketed for animals. There are still people who don't use store-bought pet foods. It's a little more work, but if done right, "homemade" animal diets can be healthier than regular pet food. I don't feed my guinea pigs pellets - they just get hay and vegetables. I make my own food mix for my spiny mice. My cats get canned cat food, but it's pretty much made up of only meat, which could be replicated pretty easily. Basically, pet food only exists for convenience.... and to line the pockets of CEO's

I think they were fed table scraps, scraps from butchers and they hunted for some of their food.

Tablescraps, leftovers, and whatever they could catch and eat. I believe that Spratts was the first version of dogfood biscuits to be commercially supplied!

If it was a dog, table scraps.

If it was a cat, whatever that cat caught for themselves, plus table scraps.

Dogs were technically wolves in the past. They hunted with us and ate the catch with us.

Cats on the other hand caught mice and other pests.

Mostly table scraps

Maybe there left over food.