I've always had a soft spot for the plan of repopulating the Great Plains with modern versions of all the extinct megafauna. We used to have camels and cheetahs and lions and more. We could import half of the African large mammals and they would have had near species analogs in the relatively recent past, geologically speaking.
GMO hyper competitive feral cat colonies that ignore birds and pollinate gmo soybeans whilst collecting for their kitten hives. Each claw is of course a stinger. What could go wrong.
There were native horses, in fact the genus began in N. America and migrated out.
Remains have been found in permafrost in Northern Canada.
They went extinct about 12,700 years ago, sometime after humans arrived.
The horse ancestor species come from the Americas and migrated to Eurasia over the bearing land bridge.
Horses were only missing from North America for 10,000 of the last 50 million years.