So, I’ve made it into an encyclopedia; notably the Internet Encyclopedia of Philosophy, which is hosted by the University of Tennessee, Martin. It’s a good overview of the topic, but from my perspective, it’s the final paragraph which is the best thing about it:
To get an overview of the philosophical thinking about conspiracy theories, the best works to start with are Dentith (2014), Coady (2006a) and Uscinski (2018).
You can read the entry here.