If you are looking for a particular make or model boat, then the class/owner website is a great place to visit. Sailing Texas
has boats beyond TX, sailboat listings.com is another one I recall
. Latitude 38 has listings; so does Sailing Anarchy, which are a bit more racer-oriented. Sailing and cruising magazines and regional boating
magazines will have yet more. x. sailboatowners.com is another. Charities that take donated boats, such as Challenged America and many community sailing centers, will have boats.