Remember chicken and pigs, too. Not useful for labour, but good sources of high value nutrition, and can be fed of scraps or whatever they find around the house and garden.
In Europe, pigs like eating acorns, which are otherwise fairly useless to humans.
Farming the white-tailed deer native to the Americas has become somewhat common in the old world and reindeer have also been domesticated as beasts of burden across northern Eurasia. AAIU, the body structure of white-tailed deer isn't very suitable for labor, they can jump very high, and are not particularly gregarious or easy to keep in herds. The North American caribou (reindeer) population only inhabits the far north and is seasonally nomadic, migrating over very long distances. Other, larger, native species like moose are usually considered too big and too aggressive to tame.
Once you've worked out a good way to leach out the tannins, acorns actually become a really useful food. There are a variety of possible methods - boiling, prolonged immersion in running water, or repeated mashing and rinsing cycles.
The American west coast is probably the most famous example of where they were widely used, with all three methods of processing in use according to local resource availability.
Long-term storage was achieved by drying and grinding into flour, oak groves were actively managed, and yields were enhanced by regular burning of undergrowth.
They were a nutritious, reliable, and low-risk source of calories with widespread availability, and the processing was time-consuming but not particularly difficult. Before the genocide, they'd have been the staple foodstuff for most people in an area stretching from the Cascades down to roughly where San Diego is today.
In Europe, pigs like eating acorns, which are otherwise fairly useless to humans.