As you can see, I've made these indices a bit more helpful than those usually found online, including notes on the intended setting, party make up & levels, and a brief description of the premise of the adventure to help you pick an adventure that's right for your group and campaign. Additionally, since a lot of folks have a favorite author or two whose work they value above others, I've listed the author of each adventure.
Issue: 21 (Dec '78)
Title: The Hall of Mystery
Author: Don Turnbull
Setting: Generic Dungeon Crawl (with Aurthurian myth references)
Levels: 8-12 (as with many early 'adventures', no such information is given, but based on the monster selection, high end Expert level PCs should suffice)
Suggested Party Make-Up: standard well rounded party, I suggest at least one cleric to support the fighter and spellcaster types. Not a whole lot of use for thieves here, alas.
Note: The author, who was also editor of White Dwarf magazine and the AD&D Fiend Folio, like many designers and DMs of the era, hosted his own ever growing mega-dungeon, The Greenlands Dungeon. This short dungeon crawl is noted as being "a section deep in" that dungeon, but no further information is provided. For more tidbits on the Greenlands dungeon, refer to early issues of White Dwarf magazine.
Description: In what might be described as an early 'one page dungeon', the PCs are tossed into a very old school, very plotless dungeon crawl. Nice variety of monsters though, and some neat teleporter 'traps' to randomly (and unknowingly, causing all sorts of fun and confusion) zap the party from place to place on the map, though. A nice option for a a session campaign interlude.
Issue: 55 (Nov '81)
Title: The Creature of Rhyl
Author: Kevin Knuth
Setting: Generic Dungeon Crawl
Suggested Party Make-Up: 3 or more PCs, ideally including one 3rd level magic user, elf or cleric and multiple 2nd or 3rd level fighters, dwarves or halflings
Description: For years, the mad magician Astylis has summoned a fell beast to terrorize the people of Rhyl with nightly raids. After the kidnapping of the prince and the theft of some royal heirlooms, the king finally sent his men into the mountains to find Astylis' lair and rescue the prince. The king's men failed, but perhaps the party can succeed in besting Astylis' dungeon, defeating his dragon (yes, dragon) and rescuing the prince?
Issue: 92 (Dec '84)
Title: The Sword of Justice
Author: Jon Mattson
Setting: Generic Dungeon Crawl
Suggested Party Make-Up: 4 to 6, preferably of Lawful alignment. Dwarves and Elves are helpful, for their racial abilities with secret doors and such, but not required.
Description: A magic sword said to be able to judge the truth of any man's words is brought out to settle a murder trial, but both the sword and the accused, an eccentric elf, vanish mysteriously during the trial! After tracking the fugitive to a run down mansion, commonly thought haunted, the party must explore the place, retrieve the sword and if possible, capture the fugitive.
An Important Note:
Unfortunately, some online indices of Dragon magazine material often label various late 1990s era material, including the so-called 'fast play' starter adventures like "The Ruined Tower", by Jeff Grubb in issue 251, as Classic D&D. These materials are not Classic D&D. Instead, they are a very dumbed down, rules light version of AD&D 2nd edition, intended to introduce new players to the game and hook them into playing AD&D. While the adventures are generally fun, quick to play and very easy to adapt to Classic D&D, the presence of such AD&D features as "Halfling Thieves" clearly show that these are not Classic D&D.