My favorites include:
58 Dwarves
59 Halflings Point of View;
60 Elves Point of View;
61 Gnomes Point of View;
62 Half-orcs/orcs Point of View;
63 Humanoids
--- "Plan before you Play" by Ed Greenwood
65 "Law of the Land" by Ed Greenwood
66 Thieve's Cant
67 Greyhawk Deities
68Greyhawk Deites (Celestian, Farlanghn,Ehlonna, Pholzus, Tritheron)
--- Weather in Greyhawk
---Thrills and Chills
69 Greyhawk Deities (Istus, Obad-hai)
70 Greyhawk Deities (Boccob, zagyg, Oldimarra)
71 Greyhawks World (Heward, Keoghtom,Murlyand, Kelanen)
--- Greyhawk Deities (Erythnul, Incubalos, Nerull, Ralishaz, Wastri)
72 The Real Barbarians by Katherine Kerr
73 Non Violent Magic Itemsby Lewis Pulsipher and Roland Getliffe
75 Beyond the Rule Book by Lew Pulsipher
---- Nine Hells Part 1 by Ed Greenwood
---- All games Need Names by Katherine Kerr
76 Nine Hells Part 2 by Ed Greenwood
79 The Fights of Fantasy Lew Pulsipher
80 Who Lives in that Castle Katherine Kerr
84 Never the same thing Twice: Scott Bennie
-A cast of strange Familiars by Stephen Inniss
85 Clerics must be deity-bound Frazer Sherman
87 Beyond the Dungeon by Katherine Kerr
88 Beyond the Dungeon part 2 by Katherine Kerr
91 Eight Devilish Questions by Ed Greenwood
91 Nine Hells Revisited by Ed Greenwood
93 The Making of a Milieu by Arthur Collins
94 An army travels on its stomach by Katherine Kerr
96 What good PCs are made of by Katherine Kerr
97 Blueprints for a Big Game by Jim Dutton
98 Detailing a Fanasty World by Jim Dutton
----Creative Magic Items
99 That's Life in the Big city by Kevin Anderson and Kristine Thompson
102 Creating a Cast of NPCs by Jim Dutton
104 The Well Rounded Thief by John C. Bunnel
---Race is ahead of Class by John C. Bunnel
---Was it Worth the Risk by Bruce Barber
105 The Well Equipped Victim by Ed Greenwood
---Travel works Both Ways by Paul Vernon
108 The role of Nature by Bruce Humphrey
109 Locals aren't all Yokels by Ralph Sizer
111 Welcom to Malachi by Becky Helfenstein
112 Armor Piece by Piece by Matt Bandy
115 Lords of the Night by Eric Oppen
---A Den of Thieves by Vince Garcia
---The Art of Climbing Walls by Vince Garcia
---Honor Among Thieves by Eric Oppen and Robin Jenkins
117 Fun without Fighting by Scott Bennie
122 Marshalling the Martial Arts by Wayne Goldsmith and Dan Salas
123 Just Making Time by Roger Moore
133 Notice Anything Different by Thomas Ruddick
148 Tracking down the Barbarian by David Howery
---- Corrected Cavalier by David Howery
171 Completing the Complete fighter by David Howery
175 Creative Campaigns: A New Recipe by Tim Schroeder
----Inventing the "Instant Adventure" by Arthur Collins
178 What not to Include by Arthur Collins
189 The Dark Continent by David Howery
---- Arms and Armor of Africa by Michael J. Varhola
----The other Orientals by Tom Griffith
----Completing the Complete Bard by Jon Winter
191 Open your MInd by Michael John Wybo II
----The Elven Pantheoen Completed by Carl Sargent
----An African Genesis by Brady English
196 Magic From the Gods: Wizard kits for an African Campaign by Michael John Wybo II
200 Familiar Faces by David Howery
----The Even More Complete Psionicist by Jon Winter
202: Mythic Races of Africa by Michael John Wybo II
205 The People by David Howery
209 The Priests of Africa by Michael John Wybo II
210 Primitive Weaponry
214 The Complete Half Elf
215 The Deities of Africa by Michael John Wybo II
Edit: More recent issues
I like both the Demonomicon articles by James Jacobs and Sean Reynold's Core Beliefs.