WGR1 Greyhawk Ruins by Blake Mobley and Timothy Brown
WGR2 Treasures of Greyhawk 
WGR3 Rary the Traitor
WGR4 Marklands
WGR5 Iuz the Evil by Carl Sargent
WGR6 City of Skulls

WGR1 Greyhawk Ruins is based on Greyhawk castle, which was previously covered (albeit by multiple authors, in a humorous setting) in WG7 Castle Greyhawk.  WGR1 takes a serious approach and is generally regarded as the superior effort.  Additionally, WGR1 has a passing reference to the Spelljammer milieu in it: page 86 of at location Z639 (tower of Zagig, level 6, room 39).  Thanks to Robert Burd for this info.

WGR3 Rary the Traitor has some missing maps... scans are available in our Library section.
 

Printing Information

Aside from WGR1, there are no distinguishable printings between modules.

WGR1 Greyhawk Ruins

• First (1990):  Angled TSR logo on rear cover and on module booklet cover.  The first map in the module (W100) does not have a color-coded elevation key.
   
• Second (Nov 1991):  Gold Angled TSR logo on rear cover and on module booklet cover.  The first map in the module has an elevation color key, showing the various colors from the map (red, pink, orange, yellow, light yellow, light olive green, dark olive green, dark purple, light purple), indicating that each represents 5 feet of elevation with red as the highest. This explains the strangely colored maps from this module.  (Thanks to Curt Gould for this info).

Thanks to Norbert Jakobs for the WGR2 and WGR4 scans.
 

Greyhawk Ruins	Treasures of Greyhawk	Rary the Traitor	Marklands
Iuz the Evil	City of Skulls