Scraping is a discovery method, not a contact method. It answers which companies exist and what they publish, and it almost never answers who to write to at any of them.
The legal position in the US turns on one distinction: collecting public pages while logged out is defensible under the hiQ line of cases, while creating an account and collecting against its accepted terms is a contract question with a different answer.
These guides cover the sources worth using, the filters that separate trading businesses from abandoned listings, and the step that always follows: resolving a named person and verifying the address before anything is sent.