Some of the lettered-numbered Castles & Crusades Adventure Modules are organized without apparent rhyme or reason, so we have a catch-all series for those modules.
From some discussions on the Troll Lord Games forums but with no official response, these are the likely meanings behind the letters:
A - Aufstrag
C - Conversion
D - Davis
DB - Dirty Bowbe
I - Inzae
S - Steve
U - Universal
As of April 2011, these are the current TLG adventure series and titles:
A0 The Rising Knight
A1 Assault on Blacktooth Ridge
A2 The Slag Heap
A3 Wicked Cauldron
A4 Usurpers of the Fell Axe
A5 The Shattered Horn
A6 Of Banishment & Blight
A7 Beneath the Despairing Stone
Umbrage Saga Box Set (Contains A0 - A5)
C1 The Mortality of Green
C2 Shades of Mist
D1 Chimera's Roost
DB1 Haunted Highlands
DB2 Crater of Umeshti
DB3 Deeper Darkness
DB4 Dro Mandros
DB5 The Conquered East
DB6 Dwellers in the Darkness
Heart of Glass
I1 Vakhund
I2 Dzeebadg
I3 Dogs of War
S1 Lure of Delusion
S2 Dwarven Glory
S3 The Malady of Kings
U1 Shadows of the Halfling Hall
U2 Fingers of the Forsaken Hand
U3 Verdant Rage
U4 Curse of the Khan
