Explore Google's Fact Check Explorer
Google provides a Fact Check Explorer tool that indexes checks published by many fact checking organizations round the world. They also provide an open API.
The demo.py script here provides some simple examples of what you can do, including getting a (partial) list of fact checking organizations and getting recent checked claims. You will need to register (free!) and get an API key, as described here and update demo.py with it.
The Fact Check API doesn't seem to provide access to a full list of fact checkers - you could make your own list from the IFCN Signatories easily enough. My code searches for some common terms and builds a list of fact checkers, but it's not comprehensive.