An agent can search with the "owner financing" filter in their search. Chances are there will not be many homes available. For an owner to be willing to finance, they must either own the house outright or have an assumable loan that will allow an wraparound mortgage.
You must be prepare to offer them security and an above market rate to be willing to take the risk. I'm not saying it can't be done, but it could be tough. Best of luck.