Many Airbnb hosts and real estate investors are searching for their next investment property. Many are searching for STR or short term friendly properties or neighborhood's (HOA).
Unlike a real estate agent, you scope out properties by reaching out to landlords and asking if they allow short term rental or corporate leases. If they do, you can curate a list depending on location and find hosts looking for a property in Facebook groups on Airbnb hosting, short term renting, ect.
You can either sell the list as a lead or charge for your time looking & reaching out. You can make a contract through Upwork.