Various giant mammals became extinct only recently - so it may soon become possible to recover their DNA and resurrect them.
Such as the woolly mammoth - no introduction needed;
the giant sloth, which weighed up to 4 tons;
the giant wombat which lived up until about 12,000 years ago. It weighed up to 6000 pounds;
the American lion
As the climate warms maybe we will find more frozen remains especially in Siberia of animals that have become extinct. That could give us a lot of DNA to work with.