List of External LDoN Guides/Resources:
The Mystic Order LDoN Guide - TMO, now Ashen Oath, wrote a very comprehensive and well illustrated, well written overview of LDoN. It covers essentially everything you need to know form a high level.
Allakhazam Wiki LDoN Guide - Alla generally has a guide/overview for all of the expansions. The LDoN one is a little thin in some areas, but still a good starting point for more information about the expansion with links to other Alla resources.
LDoN Cardplace - This is a website that lets you search all of the LDoN group loot that is sold by merchants, using this tool you can find any item that is sold for points and filter by class, Wayfarer Camp, item type, slot etc.