Here are indices for some of the study groups that have been explored over the years. The Liber 418 index is a work in progress, once I get the time to gather all the threads. I'll be leaving the Book of Law study group sticky as a resource as well as any currently active groups.
Thoth Study Group - Table of Contents a huge list of threads dealing with many, many aspects of the Thoth deck
Book of Law Study Group a completed study group of every verse in the Book of Law, in order
Liber 418 Study Group an incomplete list of the Liber 418 study group threads
Book of Thoth 2015 Study Group Index a new study group dealing with the Book of Thoth (in progress)
Be aware that this list is not exhaustive, many topics have been discussed over the years. If you're looking for something specific, a search
using the Google box is your best bet.