Or, 'the crazies, as Rep. Peter King (R-NY) calls them.
The Hard-Line Republicans Who Pushed John Boehner Out. (FiveThirtyEight, 9/25/2015)
No website, no official roster.
As a group, Freedom Caucus members are more male and more conservative than the rest of the Republican caucus, with less time in office, and they were elected in districts that lean more heavily Republican than the typical Republican representative’s district.