The only type of real comps there are, are sold comps. If a property is still on the market, or never sold, it's not a comp.
Check with a Realtor.
Often, county tax assessor websites are online. They'll show the last time a property sold, and for how much. But it can be difficult finding what you need (properties sold within the past 3 or 6 months similar to yours within 1/2 mile or so of your property) on county tax websites. A Realtor can do it in a matter of minutes.