At long last we now have a comprehensive list of codices, supplements, dataslates, and Imperial Armour books cataloged on the Ruleset page. Players may select their armies using units and formations from these sources, following the tournament rules for Army Selection.
This list of approved sources of units is now over 60 published sources, so players have an unprecedented amount of choice for how to compose their armies. Army lists must be submitted to the organizers for validation so when preparing your list be sure to note the source(s) that your force is selected from.
There have been a lot of changes to the 40k ruleset over the past year, and it has been a great deal of effort to organize and present this list. So should something not be listed, please let us know.