but a lot of them don't execute a lot of people. The big three (TX,FLA,OK) account for like two or three times as many executions as the rest of the states combined.

Texas of course is responsible for two of the clearest cases of executing innocent people: Carlos De Luna and Cameron Willingham. The former is the subject of a completely damning investigation by the Innocence Project at Columbia University called "The Wrong Carlos" (I have it if anyone wants a link) and a couple of other books and films which are not up to the standard of the NWU book but good none the less.

Cameron Willingham's case is covered in a film, "Incendiary" which is also superb but infuriating (the lizard-tanned scumbag governor Rick Perry in particular is repellent). I have the film but it's hard to find online. There's also an excellent article on the case by David Grann:

https://www.newyorker.com/magazine/2009/09/07/trial-by-fire