Not sure of the years, but I know there was the Ravenloft (original module) reprint, Star of Kolhapur, Lost Shrine of Bundashatur, Moonlight Madness, and I think thats all...  there were also a few other exclusives sent out during the 90's (Secrets of Hogunmark comes to mind).

Here's a starting list of the more well known ones.  Some of these could probably be disputed as to whether they were widely distributed or really just for RPGA members.  The latter ones are more common and later releases.  Of course, Polyhedron contained many modules.  I've added the levels for those of you that are interested.

R1    TO THE AID OF FALX 5-9
R2    THE INVESTIGATION OF HYDELL 5-7
R3    THE EGG OF THE PHOENIX 5-9
R4    DOC'S ISLAND 6-10
RPGA1 RAHASIA 1-2
RPGA2 BLACK OPAL EYE 2-3
RPGA3 FORGOTTEN KING 4-7
RPGA4 THE ELIXIR OF LIFE 4-7

9568  MOONLIGHT MADNESS 4-6
9573  DUNGEON CRAWL, THE LOST SHRINE OF BUNDUSHATUR 8-10
9590  KIDNAPPED ALL
11397 RAVENLOFT: 25TH ANNIVERSARY 5-7
11445 TSR JAM 1999, SILVER ANNIVERSARY ALL
B0778  WAND OF ARCHEAL 6-8
B1732 THE FRIGHT AT TRISTOR 1-3
****  STAR OF KOLHAPUR 5-8