The "Rooted" threads started to take up a lot of space, so I've decided to gather some of the guides in one rooted post.
Feel free to post any suggestions of links below.
Comprehensive Shade Guide AO-Universe
Maxed out Shade Complit Backstabber of RK2 (Complit Item Reference)
Shade Research Posted by Slimsobe
Shade Solo Leveling Guide by Bladepoint (Good guide; although difficulty based on gear years ago)
Shade Jobe & Tier 1 Armor Guide by Shaduky
What is Backstab? (explanation). by Aelynn
A List of Shade Weapons by Slybabe
Shade For Beginners and Mini-Guides by Munkeezon
Spirits, all about them by Yo****aka / Xpie / ShadowMaw
Lets combine a guild for known locations where certain types of weapons drop! by DarkSeeker
Vulc's Twink guide to the Blood-soaked Cloak of Dishonour (Good item reference)
Atrox and the Blood-Soaked Cloak of Dishonour By Tered (Good item reference)
How to acquire Tragic+ spirits by kyleb
Legacy
These guides are much too old to be reliable information for those who would need them.
Coldshade's Shade Guide by Strifethorn
Vlanice's Shade Guide by Vlanice
Aelynns guide to the Shadows. by Aelynn
Shade usable Neck/Back/Head item list by Doul
DB/alb bracer comparison - More Comparisons by Chao
1750 Computer Literacy by Sly