The above chart is from mediabiaschart.com, where you can see their methodology that determined how sources are ranked. Here's a link to the latest version of the chart:
Neutral, Non-Partisan Sources
Associated Press - independent, not-for-profit news cooperative headquartered with coverage in over 100 countries.
Economist - offers authoritative insight and opinion on international news, politics, business, finance, science, technology.
CSPAN - provides access to the live gavel-to-gavel proceedings of the U.S. House of Representatives and the U.S. Senate, and to other forums where public policy is discussed, debated and decided––all without editing, commentary or analysis and with a balanced presentation of points of view.
The Center for Public Integrity - one of the country's oldest and largest nonpartisan, nonprofit investigative news organizations
Cook Political Report - an independent, non-partisan newsletter that analyzes elections and campaigns for the US House of Representatives, US Senate, Governors and President as well as American political trends.
FairVote - a non-partisan, 501(c)(3)h non-profit organization that seeks to make democracy fair, functional, and more representative.
Real Clear Politics - News, political opinion and commentary, and the political issues of the day.
Forbes - Core topics include business, technology, stock markets, personal finance, and lifestyle.
Cato Institute - a public policy research organization dedicated to the principles of individual liberty, limited government, free markets and peace.
PBS News Hour - evening news broadcast offering news updates, analysis, live studio interviews, discussions
Politico - Political news about Congress, the White House, campaigns, lobbyists and issues.
National Public Radio - delivers breaking national and world news. Also top stories from business, politics, health, science, technology, music, arts and culture.