Here is a (growing) google doc listing the api endpoints for plex media server. If you'd like to add to this please PM me.
PS: I noticed that with a lot of these plex would first perform an HTTP OPTIONS on the endpoint to (I guess) verify that it indeed belongs to plex. The response of which was only headers, mainly, Access-Control-Allow-Methods and Access-Control-Allow-Headers. You can look more into it via chrome developer tools or firebug (I think. I actually dont use firefox (: ).
I can contribute. I Know a large portion of the api.
EDIT. I only wonder if a google doc is the correct place for this.
