News Sources that can be accessed on the open web, along with links to their editorial policies and codes of ethics: (note where these fall on the Media Bias Chart).
The newspapers listed below are widely considered national newspapers of record, with links to their editorial policies and codes of ethics:
New York Times Standards and Ethics
Wall Street Journal Policies for Employees
The Los Angeles Times Code of Ethics
The Washington Post Standards and Ethics
According to Michael Caulfield's Web Literacy for Student Fact-Checkers, these papers are "distinguished" in two ways: "They are rigorous, showing attention to detail and having accountability in their editorial processes." AND "They have a truly national view and attempt to be the best possible record of what happened in the nation (not just a region) on a given day."
"National Newspapers of Record." Web Literacy for Student Fact-Checkers, 2017. Press Books. Accessed 13 Aug. 2018.