Here is a list of where to get them by zone. I made this list for my own quick reference and thought I'd share it here.

If you want to see the stats go here http://aoc.is-better-than.tv/
It's a great site but just a little annoying when I'm in a K6 and wondering if anything might drop for my class.

Abyss of Kun Whu
-Yun belt

Cavern of Malice
-Yag shoulders

Celestial Necropolis
-Yag hands

Coppice of the Heart
-Hyrk belt
-SC hands

Den of the Crowmen
-Yun hands
-Book: Rebuke 6

Enigmata of Yag
-Book: Repulse 6

Jade Dugout
-Scholar's hands

Kang Pagoda
-Yag belt

Palace of Yun Rau
-SC shoulder
-Scholar's belt

Pillars of Heaven
-Yun shoulders

Reliquary of Flames
-Hyrk hands
-Hyrk shoulders
-SC belt

Vortex of the Storm
-Scholar's shoulders