This is intended to be a comprehensive list of creatures that have appeared in various Dungeons & Dragons works. Each individual list covers a span of years by edition of the game, with monsters being listed chronologically by book in which they appeared.
Although efforts have been made to include all creatures, there are likely to be omissions and other errors. At any particular time, there will be variations in the level of brief detail, and there are some duplications, not all of which are errors as there is some name duplications amongst the creatures.
The original edition of Dungeons & Dragons consisted of a boxed set by Gary Gygax and Dave Arneson printed in 1974, and several pamphlet-sized supplements printed through 1976. The volume "Monsters & Treasure" in the original set, and the supplements (Greyhawk, Blackmoor and Eldritch Wizardry) included a section of monsters.
This edition of Dungeons & Dragons began in 1981, as a revision of the introductory Dungeons & Dragons Basic Set established it as a separate version of the game that ran concurrently with both 1st edition and 2nd edition Advanced Dungons & Dragons until the line was ended in 1994. The Basic Rulebook collected many of the monsters from the previous D&D supplements, and the subsequent Basic Set, Expert Set, Companion Set, Master Set, and Immortals Set all added more new monsters to the game. The Creature Catalogue expanded on these sets even further, collecting monsters that had appeared in basic D&D modules and adding new monsters as well.
Introduced in 1977, the Advanced Dungeons & Dragons game built upon the original edition of D&D. This edition also introduced the concept of a Monster Manual, a separate book to deal with just monsters. The original Monster Manual collected the monsters from the original D&D books, and other sources, and expanded on the monster format. The original Fiend Folio and Monster Manual II were also printed during the run of AD&D 1st edition, and numerous monsters appeared in other modules and game supplements at the time.