| Code Title Levels Author(s) Published Notes | |
| X1 The Isle of Dread 3–7 David Cook Tom Moldvay 1980 Included in Expert Set. Ranked 16th greatest adventure of all time | |
| X2 Castle Amber 3–6 Tom Moldvay 1981 Ranked 15th greatest adventure of all time | |
| X3 Curse of Xanathon 5–7 Douglas Niles 1982 - | |
| X4 Master of the Desert Nomads 6–9 David Cook 1983 Nomads Pt 1 | |
| X5 Temple of Death 6–10 David Cook 1983 Nomads Pt 2. Given 10/10 by White Dwarf. | |
| X6 Quagmire! 4–10 Merle M. Rasmussen 1984 - | |
| X7 The War Rafts of Kron 9–12 Bruce Nesmith 1984 - | |
| X8 Drums on Fire Mountain 5–8 Graeme Morris Tom Kirby 1984 UK made | |
| X9 The Savage Coast 4–10 Merle M. Rasmussen Jackie Rasmussen Anne C. Gray 1985 - | |
| X10 Red Arrow, Black Shield 10–14 Michael S. Dobson 1985 Battlesystem required; uses elements introduced in X4-X5, but not a continuation of that series as such | |
| X11 Saga of the Shadow Lord 5–9 Stephen Bourne 1986 - | |
| X12 Skarda's Mirror 5–8 Aaron Allston 1987 - | |
| X13 Crown of Ancient Glory 7–10 Stephen Bourne 1987 Requires Companion Set | |
| XL1 Quest for the Heartstone 5–10 Michael L. Gray 1984 Tie in to action figures. Given 4/10 by White Dwarf. | |
| XSOLO Lathan's Gold 4–6 Merle M. Rasmussen 1984 Solo Module | |
| XS2 Thunderdelve Mountain 7–9 William Carlson 1985 Solo Module | |