(Fact-check sites in no particular order...)
"PolitiFact is an independent fact-checking journalism website aimed at bringing you the truth in politics. PolitiFact's reporters and editors fact-check statements from the White House, Congress, candidates, advocacy groups and more, rating claims for accuracy on our Truth-O-Meter."
A nonpartisan, nonprofit 'consumer advocate' for voters that aims to reduce the level of deception and confusion in U.S. politics. Monitors the factual accuracy of what is said by major U.S. political players in the form of TV ads, debates, speeches, interviews and news releases.
Vote Smart is a non-partisan, non-profit organization that provides factual information on candidates, including bios, voting records, positions, ratings, speeches, and funding.
Politico is a journalism organization focusing on political news. The organization aggregates results from various polls and allow users to filter poll results by state, office, category/issue, date, and source.
New York Times
Fact-checking by the New York Times.
The Washington Post's Fact Checker
Fact-checking by the Washington Post.
The Internet Archive's Political TV Ad Archive
Archives political TV ads in 2016 primaries married with fact-checking and reporting from award-winning journalism partners. The site includes "downloadable data on how often it has aired, where, and when in 20 TV markets throughout eight key primary states.
"SciCheck feature focuses exclusively on false and misleading scientific claims that are made by partisans to influence public policy."