There was a WIKI but very little additions from the community, it’s really up to me to do that, most users here are musicians not programmers.
All classes bound to Lua from JUCE are clearly seen in special .cpp files in the git repo, each file represents one class (or more in some cases, when the classes have tight relationships like Graphics and Audio*).
You can see the files here: https://github.com/RomanKubiak/ctrlr/tree/master/Source/Lua/JuceClasses
on the bottom of each file there is a section that binds classes, methods, static members, enums to Lua so you can see what is available.
Also i Lua when Ctrlr is started you have 2 magic methods that show what is really available at runtime.
Those methods are how() and what(OBJECT), how prints all available types available, and what(OBJECT) prints all available members/methods on the OBJECT passed to it. It’s really helpful.