The name, Exxon, is a good example. Click new user. Search both federal and state databases. Click for a report of the findings. Or hire an intellectual property lawyer.
Law firms use huge privately owned databases and professional search firms.
Try different search phrases. If you tap in the names incorrectly, an unforgiving search system may return the wrong results. Always click on help first for effective search techniques. Search the Internet before hiring an attorney. You might be able to eliminate some of your name choices.