Very likely a cherry. They are notorious for producing root suckers from the grafted understock, often at a significant distance from the actual tree.

If they are in the lawn, mowing is your best defense. Or you can attempt to pull them. There is also a product called Sucker Stopper (Monterey) that supposedly will deter - but not prevent - their reformation once they have been removed. As long as the tree is still alive, they will continue to be produced.