AllSides - Analyzes news stories by sharing information from sources skewing left, right, and center on the political spectrum.
Google FactCheck - Aggregates recent fact checks from around the internet.
FactCheck.org - A nonpartisan, nonprofit “consumer advocate” for voters that aims to reduce the level of deception and confusion in U.S. politics.
LeadStories - A fact-checking and debunking website.
Snopes - A well-known fact-checking website.